Silent 700 Model 707 (built-in modem)

[Divarin]

Has anyone had any luck using a Silent 700 model 707 to dial into a dialup BBS over VOIP (or even POTS)? I've been able to dial into BBSs using a PCI modem in an XP machine however when I try with a Silent 700 model 707 it just hangs up right away.
I found the manual here: http://www.bitsavers.org/pdf/ti/ter...7_Data_Terminals_Maintenance_Manual_Feb84.pdf
I didn't see a way to set the communications parameters to 8N1, it seems to be fixed at 7 data bits and 1 parity bit, although I could change the parity between even, odd, mark, and space.

 

[VERAULT]

Interesting. Well I never got a silent 700. I tried a few times but the sale didnt go through. I have a TRS-80 PT-210 and I was able to get that online with a wifi modem ( I have a thread or two on the subject). I havent owned a Pots line since 2003.

Just curious does your model have a serial connection or just acoustic couplers?

 

[Divarin]

The 707 only has a built in modem (so one RJ11 jack). I actually picked it up to serve as spare parts for my model 703 which has a serial connection. The 703 works fine and I use it occasionally.
The 707 was really cheap I think because it wasn't obvious what it was (listed on shopgoodwill.com a long time ago). It has a branding on it says "The MOORE personal terminal" and only on the bottom does it say "Texas Instruments". But I recognized what it was and that since it's listed at like $10 and no one else is bidding I should pick it up if for nothing else to be spare parts to keep my 703 going especially after the damage mine received in shipping as described in this earlier post.

Still, it would be nice to use the 707 if possible. Of course I could try to connect it to something else locally and just make sure the two systems are using the same data bits and parity but not as fun as calling a BBS.

 

[VERAULT]

The 707 only has a built in modem (so one RJ11 jack). I actually picked it up to serve as spare parts for my model 703 which has a serial connection. The 703 works fine and I use it occasionally.
The 707 was really cheap I think because it wasn't obvious what it was (listed on shopgoodwill.com a long time ago, probably over a year ago). It has a branding on it says "The MOORE personal terminal" and only on the bottom does it say "Texas Instruments". But I recognized what it was and that since it's listed at like $10 and no one else is bidding I should pick it up if for nothing else to be spare parts to keep my 703 going especially after the damage mine received in shipping as described in this earlier post.

Still, it would be nice to use the 707 if possible. Of course I could try to connect it to something else locally and just make sure the two systems are using the same data bits and parity but not as fun as calling a BBS.

Anyway to interface the components that make the 703 have a serial connection onto the 707?

 

[Divarin]

Anyway to interface the components that make the 703 have a serial connection onto the 707?

maybe but the BBS that started this whole thing (Hidden Reef) is dialup only so I was hoping to use it as a way to log into that board, plus maybe some other dialup only boards (if I can find any)

 

[VERAULT]

maybe but the BBS that started this whole thing (Hidden Reef) is dialup only so I was hoping to use it as a way to log into that board, plus maybe some other dialup only boards (if I can find any)

POTS only? It doesnt have a telnet backend?

I hear you and applaud the desire to do so.. But after over 20 years of no copper phone service I throw away (if I cant rehome them) most modem specific things I encounter (or harvest components from them). I havent dialed another computer since 2002 or 2003.

I have thought about this particularly on my Actrix Maxtix computer with acoustic couplers (actually the TRS-80 PT-210 has couplers too) about using them somehow.... I wish there was a device to transmit data to them from a wifi modem so you could still use them... That would make these devices useful again.

 

[NeXT]

300bps should be acceptable for most VoIP. Are you at all able to monitor the line to see if a carrier signal is missing or weak?

Port settings on the receiving end shouldn't matter until after it raises the CARRIER DETECT flag and establishes a link. Another thing is rather than a full DTMF circuit a cheaper and still then viable option was to run the hookswitch relay and pulse rotary numbers. Is your POTS bridge able to recognize rotary dialing?

 

[Chartreuse]

Only thing I'd make sure on the voip is that you have a fixed size jitter buffer, and ideally G711u compression, though 300 baud should work as long as it hears the far sides tone, even if you get random line noise and corruption from poor line conditions. There is the difference between Bell 103 and V.21 tones though most modern modems on the far side should support both. If you listen in to the handshake with a phone plugged into the same line you should hear the other side put out a tone, then your local modem will respond with it's own and both will remain steady and then you'll hear the data from the remote side changing its tone at a kind of scratchy sounding pace. If you just hear the far side playing its tone and isn't hearing anything back, you'll typically hear it try a different tone (v21 or fax IIRC) for a few seconds more before giving up.

 

[justin423]

If someone ever came out with an add-in board that adds the line drivers and a DB-25 connector to the 707, they would be much more useful and could probably sell a few of them.

 

[RCourtney]

I obtained a 707 and am adding the DB9 full pinout board from Adafruit. There is a signal line that goes to pin 9 on the modem chip. Taking it low though a tiny DPDT toggle switch will tristate the RCVD line. The !FORCEOFF of the Adafruit board ground should be removed when needed for direct RS232. DTR needs to be asserted for the computer to communicate usually as well.

 

[Divarin]

I obtained a 707 and am adding the DB9 full pinout board from Adafruit. There is a signal line that goes to pin 9 on the modem chip. Taking it low though a tiny DPDT toggle switch will tristate the RCVD line. The !FORCEOFF of the Adafruit board ground should be removed when needed for direct RS232. DTR needs to be asserted for the computer to communicate usually as well.

Interesting I didn't this was a thing. Do you have a link? I'd like to look into it.

 

[RCourtney]

Page 88 of https://archive.org/details/bitsavers_titerminal1Model703707DataTerminalsMaintenanceManu_12495052 has the schematic.
Pin 9 of U4 TMS99532 when brought low puts the RCVD line in high-impedance state. Use one side of a DPDT switch.
Normal use of modem connect pin 10 of U7 back to the modem thru the DPDT switch.
https://rocelec.widen.net/view/pdf/cusmx16t28/TXIIS145563-1.pdf MODEM chip
https://www.adafruit.com/product/5988 Uses the MA3243 level convertor.
https://www.ti.com/product/MAX3243

The Adafruit PCB unfortunately extends beyond the connector shell and needs to be trimmed flush.
Wire !FORCEOFF low when the 707's modem is being used using the other half of the DPDT switch.
Connect DTR to Vin so your computer knows when the 707 is powered up.
Jumper RTS to CTS if needed by your computer.

I'll try to post more pics of my installation soon.

 

[RCourtney]

Page 88 of https://archive.org/details/bitsavers_titerminal1Model703707DataTerminalsMaintenanceManu_12495052 has the schematic.
Pin 9 of U4 TMS99532 when brought low puts the RCVD line in high-impedance state. Use one side of a DPDT switch.
Normal use of modem connect pin 10 of U7 back to the modem thru the DPDT switch.
https://rocelec.widen.net/view/pdf/cusmx16t28/TXIIS145563-1.pdf MODEM chip
https://www.adafruit.com/product/5988 Uses the MA3243 level convertor.
https://www.ti.com/product/MAX3243

The Adafruit PCB unfortunately extends beyond the connector shell and needs to be trimmed flush.
Wire !FORCEOFF low when the 707's modem is being used using the other half of the DPDT switch.
Connect DTR to Vin so your computer knows when the 707 is powered up.
Jumper RTS to CTS if needed by your computer.

I'll try to post more pics of my installation soon.

Correction: 3PDT you need CDET to be switched to ground when using RS232 as well.

 

[RCourtney]

I changed the schematic and am posting it here.
The three important lines are only switched.
The highlighted chips are the ones of interest.

 

[RCourtney]

The best spot to mount the serial board is on the lid's left side over the modem's transformer.
Be careful when drilling the two holes and milling the opening for the connector, the plastic may be brittle with age.

The toggle switch will be mounted nearby.

 

[RCourtney]

A RJ45 to DE9 connector now can be attached to the serial board.
The 3PDT toggle switch fits in the space next to the board.