curiousmarc
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My TI Silent 703 terminal is overclocked!
🕑 Added 2021-11-06 21:11:48 +0000 UTCNext in our unboxing was the TI Silent 703 from eBay. This one started strong, printing its waterfall test with no problems, in eerie silence:
Still in local mode, I discovered it had two character width settings. One yielding a standard 80 characters per line, and the compressed one yielding 132 characters per line, like an IBM printer:
Hooking it up to another serial device was more difficult. It is very picky about hardware handshake lines. It wants 3 of them active before it starts to do anything: CTS, DSR and CD.
Fortunately, now I have a working HP 4957A to test it with. I can toggle all these lines from the 4957, and see them on the front panel. See the green lights at the bottom right, every control line is active.
But although it started transmitting, I received what looked like garbage, 7F and 7E as decoded on the 4957. See the non highlighted text, which is receive. The transmit from the HP is the highlighted lines, but it did not generate the correct characters on the TI 703 either.
Looks like the link is not set at the right speed. But I double checked, I am set correctly at 300 bauds. This is the one and only speed of the Silent 703. I finally decided to look at the bits with the o'scope, and surprise, surprise, my bits are 4x faster than I expected. This Silent works at 1200 bauds! Must have a turbo added to it.
I didn't even know such a 703/1200 existed. There is no mention of it anywhere. There was a 700/1200 and a 707/1200 in the later years. But looking at the back of mine, it just says model 703. Well, fine, I just got a screamer.
After changing to 1200 bauds, bidirectional communication is established:
Now I can try to connect it to Peter House's donated serial-to-GPIB gadget that we unboxed in the same video. Here I use the Silent to drive a pile of HP Panaplex displays via HP-IB
Just for kicks, I tried Peter's box with the ASR 33 Teletype, at 110 bauds. Works too, but not silent at all!
Marc
Comments
Joel
A silent Model 33 Teletype would be a hellofa thing.
CuriousMarc
@Michael, indeed it was pretty difficult to get it to print that fast. To keep up with 1200 bauds, they had to invent a double wide head that could print two characters at once. I think this is what I have.
