1 (edited by Shiru 2018-03-24 18:10:57)

Topic: AON, project in progress

Please note. This is a long-term project of mine that has low priority and may come to fruition in some future (or not). I don't know when I will have time to work on it, but once I do, I will post updates and write ups in this thread. I just thought it would be cool to share the inception and development process of the idea with you, hardcode 1-bit entusiasts, as it may have more interest to you than the actual project, and maybe could provide you with ideas and inspire to do some unusual and bizzare stuff too.

Some history

AON (Avtomaticheskij Opredelitel Nomera, roughly translates as Auto Caller ID) is a product of early spontaneous small business that exploded in Russia just along the fall of the Soviet Union (early 1990s). It is a land line telephone device, or an add-on device to a normal telephone, with the killer feature being the built-in Caller ID function, plus things like contact list, alarm clock, calculator, speech synthesizer, answering machine, and such. Kind of early smart phone, as it was seen back then, long before any cell phones. Caller ID service was implemented by the land line provider infrastructure to be used by special government services such as police, but was totally not seen in consumer devices before. Even push buttons phone was something of luxury high tech at the time, with most of phones around the country being rotary dial ones from 1960s. Tone dial support was almost absent at the time, and remains uncommon in Russia even today (pulse dial in most places).

AON devices got huge popularity - at some point like it was in like every 2-3nd house. About a hundred of versions were designed, developed, and produced by thousands of individuals at their homes - electronic engineers who lost their jobs or income at the difficult times of USSR dissolution, but now available opportunity of private business. It was kind of blend of DIY and business, very similar to that happened with ZX clones in Russia that first were constructed and produced by enthusiasts as well. Some of those individuals later formed legit small business as a company, and kept production active up until 2004. Since late 90s, phone line operator wasn't happy by the increased load to their infrastructure that previously wasn't even considered as a paid option. They tried to make it such, with very limited success at first - no one wanted to pay, yet it was impossible to block it separately from the main services until a major update in the land line infrastructure that happened in 2000s. Land phone popularity went down greatly with major spread of cell phones by then, so the era of AONs has come to end.

Being mostly private one-person operated business, the devices were'n developed as an actual commercial product, like a phone with its own exterior design and casing. It was rather a PCB that was built into some existing push button phone. At very first it was targeted to the only relatively obtainable model in USSR produced by the Latvian VEF company (VEF-TA-12), so the board was designed to fit the tricky outline of the phone shell, complete with LED display and buttons placements. Later, with the flood of imported push button cheap phones after 1991, Z80 board was redesigned to be smaller and universal, allowing to embed it into many different cases. Clones of the 90s Panasonic office phone design were among the most popular ones, but countless other kinds were available as well, as each individual produced AONs with whatever parts he could obtain.

Now we're getting to the most interesting part. All AONs inside is a mere single board 8-bit computer with very basic architecture, kind of a crude MCU.

At first it was an Intel 8080 clone based design, it had a few versions of the firmware with pretty limited functionality. Very quickly it got changed to Z80 (imported, later cloned), with 8255 and 8253 on the board. Boards were mostly made with Soviet-produced parts (clones of 74xx, Intel, and Zilog chips), including the only available back then 7-segment LED display with very tiny digits - you immediately recognize its look if you seen it once. Build quality of the devices of this period was a total disaster - hot glue, adhesive tape, and almost no screws all over the place - yet it still works even 25 years later. Z80 version remained the most popular design, with two main kinds of the PCB (large VEF-specific and 9x10 cm universal one) produced. Dozens of firmware versions (Alfa, Fortuna, Julia, Lira, Selena, Vega, and the incredibly popular Rus), as well as dozens of revisions has been made for this design, with different functionality and user interface. These could be interchanged with very minor modifications to the board, if any, so it makes kind of standardized platform. The simplest firmware was just 8K ROM, most advanced ones became as large as 64K.

In later years a new Intel 80C31-based hardware has been designed to improve functionality and cost even further. Cheap Chinese electronic parts became available at this point, so they were used more often, including larger and better LED displays, but still mostly done with chips in DIP packaging, so it remained easy to modify. These aren't as common as Z80 ones, though, but very interesting nevertheless.

Today these old phones relatively easy to obtain in Russia, about $5-15 used, as they no longer have much use. Some enthusiasts were using them as an MCU to control some stuff such as machinery, or a smart house, or a car computer, as it is cheap and very easy to hack and modify. A small self-contained device with 12 or more push buttons, 9-digit 7-segment LED display, Z80 or 80C31 inside, capable to produce audio through few outputs, capable to sample analog input (phone line), usually has ROM in a socket - you know where I'm coming from.

The original VEF-TA-12 based design. Display put to the place where the paper note originally located, so it looks like it is actually designed to be like that.

The most common Panasonic clone design. Also common for the later 80C31 devices. White was the most common, but there were other colors, and different number of extra buttons (shortcuts to different features).

Random chinese phone based design, lots of such stuff.

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Re: AON, project in progress

Wow, I had no idea these things existed. Very much liking the sound of this - a platform that's totally obscure yet easily obtainable.
What exactly are your plans with it, then? Some kind of effects box?

3 (edited by Shiru 2018-03-24 13:46:12)

Re: AON, project in progress

Nostalgic things

There is also a personal retro computing nostalgic factor that may feel kind of weird for you, but still. Back in the 1980s electronics and computer related stuff in USSR mostly were both rarity and luxury. People weren't yet much familiar to home computers, electronic games, video recorders, TVs with remote, FM radios, and such, it all was a technological novelty coming directly from foreign movies and sci-fi books. In the very late 80s these things started to get imported and appear on the black market under insane prices, and with the fall of USSR all kinds of imported and local built electronics flooded the country - you probably have heard of Spectrum clones and Dendy, as few examples of this.

For us kids of the time all kinds of previously unseen technology were extremely fascinating. Casio watches with melodies, Chinese sound effect keychains, Game&Watch clones, Brick Game (Tetris electronic game) - everything caught our curiosity and attention. We loved to explore its capabilities, disassemble it to see what is inside, and so on. AONs became part of this too. Besides the ever-fascinating clever use of the 7-segment LED display that used to produce cryptic text messages (Ln Hold), one thing we appreciated a lot was the sound. Right from the excerpt from the Mikhail Glinka's 'Glory' that played during power up sequence of the Rus firmware (originally a choir piece that sings 'Glory to Russia', akin to the firmware name that is short for Russia), to a few dozens of built-in ring tones and alarm melodies, which were versions of classical and popular music. We listened and loved to recognize the famous songs in this basic square tone computer renditions. As you may guess, with Z80 and 8253 on board it was all monophonic 1-bit square wave music, albeit nicely programmed. One missing historic piece that alongside the Speccy and NES music got many of us here interested in computer music in general.

A bit later the Rus firmware was upgraded with speech synthesis - male then female voice that could say the incoming call phone number, or current time, and some other things, constructed of pre-recorded words, like old talking clocks did. It also could be used to know who was calling when you're not at home, you could call to your own number and use tone dial phone (or portable DTMF beeper device even!) to enter password and hear the speech synthesizer talking you through the call list. It was very impressive at every level, and voice quality was pretty nice for the time. Think of how voice clips were impressive in early computer games.

Close friend of mine at the time (mid 1990s) was involved into production of AONs, his father ran that private business, so he helped with soldering and assembling a ton of them. Thanks to this I learned a lot about the internals, and was also fixing and upgrading AONs for my friends time to time. So it provided me with some early digital electronics skills.

I first got the idea to use the hardware to produce some sounds back in 2014, when I was thinking of creating a simple 1-bit DIY synth and was considering to use Z80. I thought I still owned a pair of old AONs that used to belong to my childhood friends in 90s, and did some research, planning, and programming of basic emulator to make further development more comfortable, with plans to create a simple 1-bit programmable drum machine out of it at first, and something more interesing eventually. Unfortunately, later it turned out both of these somehow went to trash during major cleanup at house at some point in 2013, and I havent't found another one. Then other stuff got priority, so I had to postpone the idea. Until now!

You can listen to some of the monophonic music here: https://www.youtube.com/watch?v=A0IKdIRfoFw. This is Rus-25 on the 80C31-based board, but the same music was in the Z80 version as well (Rus firmware went to 23rd revision there, then moved to the new HW).

You can hear the speech synthesiser in this boring and shaky video, as well as see some of the interface. Again some of 80C31-based versions. https://www.youtube.com/watch?v=SOHX96BbhCk

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4 (edited by Shiru 2018-03-25 13:04:48)

Re: AON, project in progress

The tech

Now let's see what these things got inside.

The 8080-based design is a rarity, because the CPU required three power voltages, was relatively slow and complex, so it was quickly replaced with a Z80 design. Thus I won't go into specifics with that one. Then there was an early Z80-based design without 8253, it is even more obscure than 8080 designs.

The most common Z80-based design has:

- Z80 running at 4 MHz. No wait states, NMI not used.
- 8253 running at 1 MHz, one channel for INT, another for sound output.
- 8255 to control display and poll buttons.
- 9-digit 7-segment LED driven by a parallel register and 8255.
- 2K SRAM, could be 8K. The 2K is most commonly installed, direct 8K installation used to be done to expand contact lists capacity. Schematics is designed for 8K, no banking. RAM can be battery backed, usually there is a capacitor large enough to keep the contents of the RAM if the device gets powered off for a minute.
- Up to 64K ROM, the usual size is 32K that fits as a whole into the address space. In case with 64K extra 32K is banked using an 8255 output line.
- Up to 7x8 key matrix, at least 12 standard keys connected, depends on phone model.
- All I/O devices conviniently mapped to the Z80 I/O space with short addressing, no memory mapped devices there.
- It even has port to start/stop tape recorder, to be used as an answering machine.

Thinking of it, it is quite a 1-bit power house. Slightly faster than ZX Spectrum, no wait states at all, fast access to all I/O, 8253 use is very similar to the one found in IBM XT, can be used for PWM and stuff. You also can control output directly with additional output bit, as well as with gate control. There is enough outputs to make stereo, or multiple outputs with analog mixing. There is a comparator that is used to sample the phone line to read Caller ID codes (a series of sine waves, frequency encoded), which is very similar to the tape interface.

The main challenges there is very limited RAM, although with 8K it gets better, and techically you can put 32K there using extra 8255 lines to control paging, and the limited user interface capabilities, especially in regards of the display. But it is also more fun then.

Interesting thing to note is that as there is no TV display and its specific timings, you can easily downclock or overclock the device just by changing the crystal oscillator. Of course it would break the original phone firmware functionality (needs to run at specific clock to detect and generate phone signals), but totally no problems for new custom firmware. The limit is the just the frequency that main chips can tolerate. Normally there is original Z80A or a CMOS clone installed that works on the standard 4 MHz and can tolerate a little bit more.

The 80C31 designs is relatively common, but not nearly as much as Z80 one. There is a number of designs. I'm not really want to work with these at the moment, so I won't get far into specs, but in short it is:

- 80C31 at 10/12 MHz
- Up to 64K ROM, usually 32K
- 2K or 8K SRAM
- No 8253 or 8255, just a few latches for I/O lines

Besides the full blown phones, there were Caller ID add-ones. They're include the same variety of the hardware and more, i.e. Z80 and 80C31 designs. The firmware is usually very similar, kind of cut-down versions of the bigger brothers, but controls are much simpler, usually just five buttons. These can be interesting too, but for now I leave them out.

Should be also mentioned that there were other more modern designs, not listed above, PIC based for example. These mostly were done as add-on devices.

Just for reference, Z80 design schematics:


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Re: AON, project in progress

The sound

One interesting topic to discuss is what has been done already in regards to the sound in these devices. Music was relatively important there, used as ring and alarm tones. At first it was all monophonic 8253-driven square wave, as you could hear in the videos linked above, but later (past Z80) designs actually got polyphony and better sound.

At first the sounds range that AONs were capable of consisted of:

- Single channel sound cues and melodies
- One bit voice samples
- DTMF signals for tone dial

As far as I know, no one tried to do 1-bit synthesis for more complex music timbres and/or polyphony on the original hardware, although you can be sure a lot could be achieved there (and that's the goal of my project), especially considering hardware PWM possibility.

With the advent of 80C31 based AONs, sound started get more advanced. At first it was still one channel square wave, but with arpeggios and stuff (Rus 27). I think the CPU power of 80C31 at 10-12 MHz is roughly equivalent to Z80 at 4 MHz, maybe a bit better, but totally different architecture creates an interesting field for experiments with 1-bit synthesis.

Now, if you somehow get tired of 1-bit and want to try something different, there is more worth to mention.

Circa 2003 people from the Rus firmware devs, now turned into Rus Telecom company, managed to get 80C51-based MCU ASIC into production at Taiwan, called R100-XP. It has been designed specifically to be used in their AONs, with most of required interfaces built-in, and the most interesting feature of it was on-die AY-3-8910 replica. Phones based on this MCU, like Rus 28 Sonata, actually contained 1990s ZX Spectrum demoscene music! It sounds just like the real thing. Unfortunately, these phones are kind of rarity and hard to obtain, as they were produced and sold at decline of the AONs popularity.

There is another Rus 28 Sonata phone as well, likely with different board revision yet the same basic firmware, that besides the AY replica has 6 channel polyphonic music with more complex timbres. I don't have much info on this, but it sounds on par with the early polyphonic cell phones, and the sound is likely produced by some MIDI chip. Maybe VS1033 (was popular back then) or something.

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Re: AON, project in progress

dang this is fascinating stuff. love to see where this leads in the future smile

7 (edited by Shiru 2018-03-25 21:24:23)

Re: AON, project in progress

Hardware review #1

This is the first of a few phones I got recently for the project. Seems that it has been made circa 1994. The board is the small Z80 universal one, the most recent parts on the board is from 1993. It has Rus 10 firmware installed, which has been released in late 1994. The build quality is the worst case scenario. Not a single screw or even termoglue to hold the stuff together. The speaker and display were glued to the plastic, but fell off, so when I disassembled it, everything pretty much fell apart. Yet it still in fully working condition!

Is it is in the worst shape, I decided to use it as the main testbed and modded it a bit later, fixed the stuff inside the case, added standard USB socket to power it from a modern power source (nearly all AONs use external 5V adapters with 7805 inside), and other connectors. ZIF socket to be installed yet, will show final mods eventually. For now the photos just show how it was originally.

External view

The 7-segment LED display, shows the idle mode with current time. That square between the numbers displays the current operation mode (can be other figures, this is default), so you can immediately recognize it is Rus firmware.

Internal view

Very simple Z80 computer it is, he said.

Believe or not, it works!

The infamous ALS318 LED display. Soviet-made, and I think it is not a clone (like most of Soviet electronics) - at least I never found the original part. The digits are extremely tiny (1.5x2.5mm), each has individual plastic lens to make them appear bigger. They're always red, no other colors.

The small Z80 board, common revision. I marked main chips with their normal Western names.

Z80 on this board is a weird beast. It is a CMOS version. As far as I know, this one was actually has been made to be used in ZX clones specifically, alongside the ZX ULA clone, yet the latter never come to fruition. This way it got the 1582 number, chip series that otherwise contains all custom ULA-based ASICs, as well as -100 after the part number, which is supposed to be the firmware version (makes sense for ULAs, makes no sense for CPU). It is also marked as KM which means ceramics package, yet it is plastic. Early 1990s were lots of fun for the post-Soviet electronics industry.

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Re: AON, project in progress

Hmm interesting, all Russian-made componenents but an NEC eeprom.
I could listen to those the single-voice musics the whole day... though the fact that they actually included an ASIC with AY clone at some point is mindblowing.

Re: AON, project in progress

Regarding the UV EPROMs. As far as i know, Soviet electronics production only managed to get 8K done with reasonable yield. To my knowledge, no UV ROM chips has been released with 16K or more - anything of this capacity in Soviet stuff were mask ROMs or imports. For things like ZX clones Z80 and ROMs had to be imported, and that was very difficult at first. Thus in early stuff such as first ZX clones you can see either 8 of 2K UV ROMs or 2 8K UV ROMs to get the required 16K. Later importing get easier, but prices on local made components were still lower, so in early post-Soviet things like AONs you'll likely will find cloned CPU (sometimes original, though), but ROMs always will be imported. Spectrums were made in large quantities, so a mask ROM with Didactic Scalica firmware was made and used eventually, but AONs were product of individuals and small groups, so it always remained to be using UV EPROM.

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Re: AON, project in progress

Super interesting stuff, thanks for posting!

Re: AON, project in progress

Hardware review #2

This is another phone I got recently, by the same price of $9. This time it is the 80C31 design example, one I have never seen before actually, but the schematics seems to be typical. It called GEOS-RUS, with GEOS being a small company that produced AONs since mid 90s. I guess the firmware (Geos Rus-20) has been modified by them to their design. It came with the manual and guarantee card that mentions it has been made May 7th 1996 and sold May 15 1996 - probably the most hot sales time it was. Crazy enough, the manual also mentions a government-issued telecommunication certificate of some sort. Well, lots of weird things were possible in Russia of 90s.

Build quality is much better than the previous example. At least it has some screws. But more interestingly, it has main PCB and keypad PCB both designed specifically for this phone model (Technica 2308, a Panasonic clone), probably because it was popular and they had a large supply of these. It still contains the original phone board as well, with most components removed and the rest only being used as mic/speaker amplifiers - common approach in AONs in general. Another unusual thing is that it still uses the old ALS318 LED display, rigidly hardwired to the bottom of the main board, while most of 80C31 designs use much better and larger displays imported from China.

External view.

Internal view. At first glance the usual mess, but now that's mostly about wires.

The main AON board is hidden under the original phone main board and actually well fit into the space and screwed to the original points. See how lots of components were removed from the old board, including the main chip.

The new system board.  You can easily see why they moved to the 80C31 design eventually. Less chips makes it even smaller than the smallest Z80 one, yet roughly equal in power. I marked the main chips with their Western names again.

Keypad board is also custom, also well fit into the existing place.

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12 (edited by Shiru 2018-03-30 11:18:52)

Re: AON, project in progress

Hardware review #3

This device is not to be used in the project, got it for $6 just out of curiosity, as I've seen a lot of similar devices in the same exact case, but with different names and marks. Turned to be very interesting indeed. An add-on AON unit called Lart-201p from December 2002, compact design of the end of era.

A very small device, can be powered from the wall adapter or 3 AA batteries, has the usual 80C31 architecture (for the most part), quite good speaker, and a cut down version of the usual Rus firmware. Actually could easily be a totally portable 1-bit music box or something, but unfortunately this late design uses all SMD parts, the ROM is one-time programmable and has no socket. The parts now is all Chinese imports - by the time it became much more accessible and cheaper, so not a single Soviet made part there.

The most fun and major difference in this particular version of architecture is that it uses serial Flash memory chip 24C16 (2Kx8) instead of the usual 6116 SRAM. As the device functionality does not suppose very frequent information changes (incoming calls list, phone book), it neiter needs much speed nor too many write cycles. Although the endurace of the chip is 1M cycles and it supposed to last really long, there were talks that the modified firmware works very inefficiently and doing lots of unnecessary writes, so the chip got worn out after 2 years of normal use, and had to be replaced.

External view.

Back side, the AA batteries compartment is there.

The inside, it has three boards - the main one, 5-button keypad one, and sockets one (not seen on the photo).

The main board with the main chips marked.

Close up on the 80C32 and 24C16. Small chip on the bottom left is sound amplifier.

Finally the large display. You can see it often in 80C31 designs.

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Re: AON, project in progress

Hardware review #4

Another piece of the add-on type of the hardware I just got out of curiosity, for $9.

Very tiny plastic box. Unfortunately, there is not a single button, or speaker, so it does not have controls and does not produce any sound - unless you consider modding, which is easy. Still, makes a very nicely done tiny single board Z80 computer to mod and hack.

The PCB inside is just 8.5x9.5 cm large, with the infamous ALS318 LED display hard mounted to the side. This is a Z80 design, one that is supposedly was used in early Z80 AONs only, no 8253 and 8255 there. Never seen it in full blown phones, though, and this is the first time I actually see it. Judging by the dates on the chips it has been made circa late 1994. I think this is one if not the most cost reduced design, with bare minimum of stuff there.

It has Soviet Z80 clone, one-time programmable 2K ROM that is unfortunately soldered in, no socket there, and somehow original Hitachi's 6116 2K RAM. No buttons means no caller/contact lists to access, so no real use for so much RAM there. Probably it was used just because it was a very common chip easy to obtain, thus cheap.

The firmware called ALFA-3, it displays the name when powered on. Supposedly the device itself also called Elektronika-Alfa-3, but I'm not too sure on this, as there is no labels on the case or board. The functionaliy is also at bare minimum, it just works as Caller ID, absolutely nothing else, not even clock. I also seen other firmware called ALFA, it was 8K large - likely for normal phone, so maybe this 3rd revision is a cut down version of this.

External view. Sorry, it just loves to collect dust.

The board, fits the case perfectly, no unused space there.

Close up on the board.

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Re: AON, project in progress

Test ROMs

Since beginning of this thread, I was slowly working on the emulator that was abandoned since 2014. It is a must to develop new firmware efficiently, also a great help to figure out details about the architecture that remain unclear due to mistakes and difference in various schematics available, such as memory and I/O maps, keypad matrix layout, and so on. Now, when it starts to taking shape (more on it later), there is something different than the flood of HW reviews to share.

Due to the nature of the platform that was almost like DIY in early years, and due to the way parts were sold in 90s, Z80 boards nearly always has a ROM socket installed (sometimes CPU and other large chips too). As neither parts nor boards were of a great quality, it often was tricky to make the thing work once you assembled it. Thus there was a number of test ROMs from different authors that can test the hardware all the way through, helping you to figure out lots of potential issues ranging from faulty chips to missing connections or short circuits easily. It is a great help in making emulator too, in fact it was a huge help to me. There is normally no such a luxury with emulator development for other platforms, even popular ones.

Test I'm using the most called PHON-LP2.ROM, from 1995. It is one of latest and most complete, judging by the very detailed doc provided with it. It is just 2K, so you can save the 8K ROM banking headache for later. The doc is of course in Russian, so I give just a brief outline of its functionality.

In order to run it requires bare minimum of properly working hardware in order to start, namely no short circuits in CPU address, data, and control lines, correct clock - in other words, functioning CPU.

First it tries to check 8255. If there is some problem with it or related parts (listed in the doc), it shows error message using single digit of the display, as multiplexed display is not possible without these parts working correctly.

Then it tests LED display and multiplexed display circuit that is also used to poll the keypad matrix, by showing each digit with all segments on, then segment by segment. You can visually see if there is something wrong and get leads to possible source of the issues. From now on test displays pseudo-text messages that specify detected issues.

Then RAM gets tested, 6116 and 6164 supported and detected automatically. At this point test can detect missing CS, RAM degradation, and other memory faults.

Test also checks if the data bus pull up resistor array installed, some firmware versions won't function correctly without it, although some makers were omiting it to reduce the costs.

8253 gets tested next. Issues with control signals, lack of RD signal can be detected. Then 8253-generated interrupt gets tested, so you can see if interrupts is not working.

Test also checks optional configuration diodes (kind of jumpers) that enable expanded keypad and other options in some firmware. I'm stuck at this part at the moment.

A dozen of other hardware checks performed then, ones that related to the analog part, such as if phone line is not connected, incoming call detection, and so one.

Finally you can test the keypad, either normal 12 button one, or expanded 24/32 buttons - press buttons, and corresponding LED segments will light up. Turned out to be extremely handy, considering a bit tricky matrix layout and multiplexing shared with the display, plus two different layouts for normal and extended keypads.

If this is still not enough, you can then go into 8255 direct control mode. It allows to enable/disable any output line using the keypad, to help you make further HW checks manually.

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Re: AON, project in progress

Hardware review #5

While I'm struggling with proper 8253 emulation, yet another item of curiosity I got for $7. This is one of the latest AONs built on the custom 8051-based R100-XP MCU, one with on-die AY-3-8910 clone.

As it is one of the latest devices of the era, made circa 2003, build quality is relatively high, and overall it looks more like a properly made consumer product rather than a half-DIY half enthusiast thing. The phone case and buttons has labels in Russian, there is a good packaging box, and a very detailed manual, all in russian too. The board inside called Venus 5, latest of that family. Besides the R100-XP there is not much parts on the board - LED driver, 24LC16 Flash, the main 512K ROM, and a bunch of amplifiers.

The ROM is in fact Flash (EN29LV040 in my unit), mounted into a socket, so it can be modded very easily - if you happen to have a ROM burner with 32-pin PLCC adapter around.

My unit has Rus-28 Sonata firmware, instead of the AY music it features 'MIDI polyphony', as it called in an official schematics book. But there is no dedicated MIDI synth chip on the board, and schematics is barely different from the AY revision (just a few resistors and capacitors). The offical docs from the maker of the Venus boards mention that since build 5713 of the firmware it has a 6-channel MIDI Wavetable Synthesiser, so it seems to be a software synth. As the AY clone is part of the custom MCU, it should be easily usable no matter what board and firmware it is, but the MIDI synth has to be somehow hacked out of the original firmware if someone would like to have it.

The MCU also has a 8-bit DAC, so the firmware features relatively smooth volume control for all sounds.

The packaging box and manual.

External view.

Keyboard close-up. The russian labels done in the cheapest way, but at least you can now have idea what the extra buttons doing, plus there is marks on the case itself for the calculator layout.

Internal view. not much is in there. Unlike all other phones in these reviews, all boards now custom made, and the battery backup pack wires is actually connected to the board.

Back side of the PCB. 512K Flash ROM is on the left.

Front side of the PCB. The R100-XP MCU is on the right. Sorry, the mark is so weak there I couldn't catch it to be visible on camera.

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Re: AON, project in progress

Modding and testing the hardware

Finally got a ZIF 28-pin socket ($3.4, with quick delivery) and ten Winbond W27C512 DIP28 Flash ROMs ($6.2) from China. The latter is just in case, of course I don't really need that many. Anyways, it now become possible to finish my modifications to the AON unit I'm going to use to occasionally test my software during developing, as well as finishing the emulator - this means relatively frequent tests, and modifications were made to make this process more comfortable. Let's see what has been done. Please note that most of the modifications is only needed to develop software more conviently. You don't really need most of them in order to just use it once its done.

First, I fixed everything inside the case, using tons of hot glue - just like it has been done in 90s.

I added socket for phone handset, to make it detachable. Also added phone line and power source sockets. The power source is now USB Type B, this allows to use any USB phone charger supply, which is really handy, or a power bank - so it is a portable now. As much portable as a regular brick. There is Reset button added that is normally not presented, but useful to do tests.

As I need relatively frequent tests, I decided to use ZIF socket, because normal ROM socket wouldn't provide reliable contact, relatively difficult to connect/disconenct, and would wear out soon. The length of ZIF socket pins and other parts on the board not allowed it to fit into ROM socket directly, so I used yet another ROM socket in between, plugged them into each other like a tower. Not really physically reliable, but it works if used carefully.

I did a hole in the bottom of the phone body to expose ZIF socket for easy Flash ROM replacement. It is a bit too tall, not allowing the phone to stand on a flat surface as it normally should. Thus I added front legs extender, that raises the front part of the body, adding missing height. Not pretty, but does the trick.

I flashed the PHON-LP2 test ROM I mentioned above using WizardProg-87 - all smooth and easy, no issues. A very handy inexpensive piece of Chinese gear, if you happen to burn ROMs time to time. As it is a 512K Flash, but AON only supports 32K, and the test itself is just 2K, I simply copied these 2K all across the 512K image using a HEX editor, to avoid cutting/grounding chip legs (extra address lines). The test worked just fine. I learned how it behaves on this particular board (no 8253 RD, no configuration diodes), and that it plays clicks and short music phrases during testing - good to know in order to make emulator work correctly.

Here is a video of the unit running the test: https://youtu.be/rR_g8js13oY

Flashing the test ROM with the WizardProg-87 burner.

Inside of the test unit. Now with extra two sticks of hot glue.

Close up of the ZIF socket. It just plugged into a regular socket then into the board, not physically fixed (yet).

Newly added reset button on the left, USB Type B socket for the power and phone line socket (just in case I need it for something) on the right.

Phone body with bottom part screwed into its place. Extended legs at the front.

With a Xiaomi power bank now it makes a fully portable Z80 micro computer.

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Re: AON, project in progress

Most fascinating, and happy to see the progress.
At the end of the video from the unit test, what's the meaning of the "40468 7"?

Re: AON, project in progress

That's 4046807 (one digit is a bit dim), a phone number of author of the test.

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Re: AON, project in progress

Wow you guys never fail to astound me !

So Shiru, what's the first beeper engine to be ported to the phone ?

Re: AON, project in progress

I'm thinking about an unique one to benefit from the strenghts of the platform, although porting something first to test the grounds is likely. Almost anything can be ported, if it does not take up much RAM (like ZX-7 and ZX-16) - there is plenty of ROM to hold a ton of song data, and CPU speed is a bit faster.

Actually, as I still have troubles with 8253 emulation and other things take priority at the moment, porting an engine or a few is a good next step.

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Re: AON, project in progress

Maybe 8253 emulation code from GPMD85 emulator could be of help?

Re: AON, project in progress

Thanks a lot for pointing this one out, didn't see it. One issue, though, is that it is GPL, and if I simply use this or MAME implementation, which is the easy way, it'll put the whole project under GPL, which I kind of dislike - I'd rather released it under PD/CC0/WTFPL. That's why I'm trying to cook up my own implementation that is not derived from MAME. Actually I'm trying to fix up my very old implementation from 2007 or so to current needs.

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Re: AON, project in progress

Ah yes, I was almost going to make a comment about the thing being GPL. However, the Borik brothers seem to be nice folks from what little contact I had with them some years ago. So they might be possible to talk to them about relicensing the relevant portion to MIT/BSD or something. Let me know if you want their contacts.

Re: AON, project in progress

Hardware review #6

With another $8 I finally got my hands on an early AON with the 'large' board that has been designed to fit into the VEF-TA-12 phone case. Although this was the most common design for first half of 1990s due to the relative availability of the phones of this model, mine is made sometime mid 1994 - the phone itself was produced May 1994, latest dates on the chips is May/June 1994, so it is one of the latest of this classic kind. It also has mods on the board made to run Rus 17c firmware (few wires to enable 64K ROM banking, some minor fixes). Surprisingly it is in the most mint condition among all units I got so far. Actually came complete with box and original phone's manual, although the box wasn't in good condition and get damaged further during delivery, so had to get rid of it.

This early large board does all the same like the small one that you seen in these reviews, just with specifics of the analog part of original VEF phone considered, or lack of it - this design replicates analog part of the VEF phone on the board, while the small board omits most of it. The most obvious difference is that huge transformer that got omited later.

Exterior view. The display is placed where the orignal VEF label has been located very conviniently, so it looks just like it was originally designed to be this way.

Closer look on the display. As you could see on the exterior view, one of digits is noticeably dimmer than others. That's not due to the dynamic refresh, it is clearly visible with naked eye. The same happened with another unit, but another digit is dim. Normally the brightness should be all even. I think this is LED display degradation that happened by some reason. Maybe this unit once froze and remained so for a long time, so dynamic refresh stopped at this digit and worn it out.

The board. The two extra wires are changes and fixes to support later Rus firmware. One of ROM pins connected to a 8255 output, providing 64K ROM banking support. RD line of the 8253 connected to RD line of Z80, allowing to read back timer registers.

Close up on the transformer and the extra ROM address line wiring. Interestingly, you can see two logic chips with proper 74xx marking. The ceramics packed EL7493J is in fact a Soviet produced chip made to be exported to other countries. 74LS04, however, seems to be an imported chip.

Back side of the board. Has hard mounted LED display and buttons of the original phone. Despite the serious looks, these buttons isn't working well, producing many missed or repeated presses, and that's not because they're old now, they always were like that.

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25 (edited by Shiru 2018-08-11 01:24:54)

Re: AON, project in progress

So, I finally made my emulator work, more or less. I used the 8253 core recommended by utz for this time being. Sorry, no docs whatsoever so far. A ton of firmwares included, so please be my guest and feel yourself a true hacker exploring them!

I can give you a crash course, though. Load 'rus23c_z80.rom' firmware. All firmwares of this branch use a system where you press * twice to enter F-unction mode, then you press a number to select a function. Press ** 5 to enter Alarm Clock setup. In most modes singular * presses switches between available parameters. Press it until you see 'PLAY 00'. Enter a number between 00 and 24. Hold down * to hear selected tune (it plays while you hold the button). Try song 21 for extra fun.

If you have issues with sound stability, check the cfg file, you can change buffer size there.

Download: http://shiru.untergrund.net/files/aonz80emu.zip


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