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Using Silent 703 as a dumb terminal

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neosunrise

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Jan 17, 2019
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Chicago, IL
I recently acquired a nice working TI Silent model 703. It has a RS-232 port on the back. I'm hoping to use as a terminal that can connect to my PC, being it a XT or 286 that runs DOS, or a Pentium that runs Windows 2000. I tried to connect the cable to my DOS machine's COM port and use CTTY to redirect the I/O devices but kept getting error message like "device is write protected" or whatnot.

What are my options? Thanks!
 
Did you try adding a null modem? A serial cable is just a straight thru, where to connect one side to the other you need to swap the transmit and receive pins on one end. Did you set the port speed the same on both sides, and the parity, # stop bits?
 
"Write protected" sounds as if the system isn't seeing your com port correctly. And yes,@tradde is correct--you'll need to connect the two with a null modem cable, since both ends are DTE.
 
Never have I seen a COM port complain about being write protected. Not even sure what that would mean. So it is likely as Chuck says your COM port is not being seen correctly. Are you sure you using the correct port for this? Does it show in the BIOS?
 
Thank you all for your replies. Apologies that the error message was not accurate. I tried again today and the error message was “Write fault error writing device COM1: Abort, Retry, Ignore, Fail?”

I used the MODE command to set up the port: MODE COM1: 30,e,7,1,P. Then I used CTTY COM1 to connect. The system was just hanging and I had to Ctrl+Break to terminate it. Then it displayed the error message. The data terminal was already set to online and the cable was a null modem one.
 
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What does your cable look like? In particular, what are the connections on the PC side for pins 4,5 and 6,8 and 20? Is this a null-modem cable?
Since this is a PC XT, whose serial adapter are you using?
This isn't rocket science!
 
Chuck(G) said:
What does your cable look like? In particular, what are the connections on the PC side for pins 4,5 and 6,8 and 20? Is this a null-modem cable?
Since this is a PC XT, whose serial adapter are you using?
This isn't rocket science!
Click to expand...

Here's my quick and sloppy adapter. I meant to just use this as a test to see if it'd work but then come back and make a proper cable but I'm lazy and never did that so I've been using this since then.

20230922_070227.jpg

"Terminal" side is the side with the jumper, in this image that's on the left:
20230922_070125.jpg

"Terminal" side
20230922_070143.jpg

"Modem" side (plastic shield on one of the dupont connectors broke off)
20230922_070203.jpg
 
I'm having problems following the wiring, but I can say definitively that you have one thing wrong--if you're going DTE-to-DTE, pins 2 and 3 (your black and white) should be swapped on one end. (RD->TD and TD->RD). Pin 7 of course, is the same on both ends. And 4-5 should be jumpered on both ends or crossed-over. See http://www.columbia.edu/kermit/cable.html and figure II-6. I prefer model A but either A or B should work.
 
hmm yeah that might explain why I still couldn't get it to work connected to my Linux box (although I was also dealing with a flaky usb to rs232 adapter at the time). works with my wimodem though which is what I wanted to use it with so this is how I've been using it.
 
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