Universal Telephone Interface with C8PDF

[lowrybt1]

I am getting set to install and test the OSI 567 universal telephone interface in a C8P-DF. The UTI manual indicates that the 567 board needs +5V, +12V and -9V. Before pulling out a volt meter and poking around, does anyone know whether a "typical" C8P provided -9VDC to the backplane? If not, any suggestions on how to accommodate the -9V requirement would be greatly appreciated. Tom

[pbirkel]

I believe that it's pin 24, when optionally supplied. Take a look at the schematic for the 574 Analog I/O board.

Be careful with your configuration because I believe that there are other boards that expect a different voltage on pin 24 ... and you may have one!

[lowrybt1]

Thanks for this advice. I'm not good with schematics. If I were to get a separate 9VDC power supply and directly wire it to the pin 24 lead on the 567 pcb board and remove pin 24 before plugging the board into the backplane, is it possible that would work?

[pbirkel]

Unfortunately there don't seem to be any schematics, or other documentation for that matter, online for the Model 567 speech synthesizer board. You seem to imply that you have some documentation in your possession. Why don't you scan & post them for community discussion? Perhaps you're only referring to the "The OSI 48 Line BUS" table, in which case you're going to need to examine your board carefully in order to derive the necessary information.

Please post clear high-resolution photos of your board, both front and back. Unfortunately it looks like the VOTRAX daughterboard/unit obscures half of the front. Can that be detached and moved aside for a good photo of what lies underneath? ("Good photos" was of sufficient resolution to read the IC markings :-}.)

Doesn't your C8P-DF already carry -9Vdc on pin 24? Seems likely (-9Vdc is used by a number of boards!), but yes, pull out the multimeter and find out ...

BTW, a typical requirement for -9Vdc is for DRAM; see the 530C.pdf schematics page 5-of-9 description of J1 and the voltage/pin assignments there.

What boards do you currently have installed?

It would be interesting to trace out the wiring associated with pin 24 on your board. I referenced the schematic for the 574 Analog I/O board (https://osi.marks-lab.com/boards/schematics/OSI574.pdf) because the final sheet illustrates a typical approach used when non-standard voltages are required. Namely that the missing voltage is generated from additional on-board circuitry (DC-DC converter marked *optional on that schematic) or is obtained from the backplane via an optional jumper (W56 on that schematic). You'll want to understand this part of your board anyway before considering injecting -9Vdc -- which probably will work but is a bit risky without further investigation of the board itself.

[Mark]

Hey that's fun!

Don't trust your OSI to have a specific power setup without measuring! I've seen 8" floppy -V power run from the OSI backplane through the floppy cable instead of providing it to the -DC floppy molex connector on one system. Any number of mods could have been done in the past. Providing your own -9V isolated power to the board will work assuming it still expects it and doesn't generate it locally.


If you could provide a nice photo of your board, I'd love to update the hardware list. (It looks like I have some mistakes in separate OSI567/CA-15V entries.)

I have a couple copies of the 8" UTI demo disk, and was able to create a possible memory map of the card. If you have the manual could you scan it or send a couple of photos of the tech specs?

The demo software uses the slightly modified OS65D3.3 home control software with RTMON, and also seems to include votrax support. Do you happen to have the votrax module as well?

Thanks,
-Mark

[lowrybt1]

Thanks for all of the insights!

The hardware I have is the OSI 567/Universal Telephone Interface board without the Votrax module installed. The manual (I have a scan of the entire manual) indicates that a Votrax module can be added to the 567. Unfortunately, I do not have the Votrax module (it was never installed on the board) and cannot find one (the VSL or VSK) anywhere. I'll take some upclose photos of the 567 board and post them here soon.

The manual is attached to this post. It includes the 567 schematics and appendices related to operation of the Votrax module for those lucky enough to have one.

Based on your helpful prompts, I went to schematics in the UTI manual and the SAMS for the C4P and C2/3 to find out more about the -9v question. You are right that the 567 board expects to find -9v on pin 24. The C8 that I have came with a 505B, 540 Rev B and 3 fully populated 520C memory boards. Per SAMS, it seems as if the 505B uses pin 24 for earth gnd. The 540B schematics indicate that there is no connection between the PCB components and pin 24. The 3x 520C's do use pin 24 for -9v. This suggests that the C8P that I'm working with has -9v on pin 24 for at least the 3 slots into which the 520C's were installed.

The slots were the 520C's resided are now vacant. I pulled those memory cards after installing the GlitchWorks RAM board.

So, it's beginning to look as if the right power configuration is in place. I will check that with my volt meter.

Somehow, I came across an .hfe file containing the 8" CA-15 demo software. This is supposed to include the modifications to v3.3 necessary to work with the UTI.

My next steps are:
1. check slots for -9v
2. try booting the CA-15 demo floppy image
3. replace 7047 IC's on the 567 board that were removed by a previous owner
4. install the 567
5. see what happens at power up
6. if all looks okay, boot the CA-15 demo image and try to initialize the board following instructions in the manual
7. if all looks okay, connect the myriad RCA jacks and wiring from the 567 to the CBT interface
8. with all connections in place, try to dial a number using demo software

[pbirkel]

According to the schematic, installed may be a PS-3 DC-to-DC converter supplying -9Vdc, if populated (see page 61, which is schematic sheet 3 of 3). There are three on-board DC-to-DC converters located side-by-side underneath the position of the VOTRAX, with PS-3 being the one by the board edge (see page 62). All three probably look like thick black blocks. Do you have all three position populated?

PS-1 derives +12Vdc and PS-2 derives additional +12Vdc from the +5Vdc supply, in the case that pin 23 doesn't supply +12Vdc.

[lowrybt1]

Curiously, PS1, PS2 and PS3 are not populated and page 63 suggests that is normal for a 567 without the Votrax installed.

[pbirkel]

Can't find that quote for myself, perhaps the not-installed references to "P51", "P52", and "P53" are typos? The schematic shows a number of modem-associated components (e.g., op-amps) that require +12Vdc/-9Vdc, so your PS-1/2/3 associated jumpers from J1 pins 23/24 must be installed and you will definitely need to supply these voltages. The parts-placement diagram doesn't indicate their location but I suspect that you'll find them adjacent to J1.

So your board operates as a 300 baud auto-answer modem with a cassette-control for audio recording/playback. Support for both pulse and touch-tone dialing is nice! Now you need a TLS and another device to "talk" to ...

[lowrybt1]

I figured the PS1/P51 was a classic OSI manual typo. I'll take a closer look at the board following your guidance.

Is a TLS a telephone line simulator? Never worked with one of those before. Looks like a cool piece of equipment.

The pulse dialing will not work over my FIOS/fiber connection even though Verizon says it should. I've tried pulse dialing with FIOS using legacy equipment and all I get back is the number you have tried is invalid. I wish I'd kept my copper POTS line, especially given the frequency of electrical blackouts where I live.