1488 requiring several supplies -- and runs hot as a pistol, too. I've got a box of both; they were about all there was to use in the market and worked well when I was using them; but don't use them much now because of the power requirements (especially the 1488) and the serious heat to be removed (again the 1488 much more than the 1489, if memory serves, but neither of them slouches in the heating department.)
Jon
On Fri, 06 Jan 2006 18:36:03 GMT, Jonathan Kirwan Gave us:
Sounds like a poorly implemented utilization. Sum Ting Wong must have done the design.
On Fri, 06 Jan 2006 18:54:51 GMT, Roy L. Fuchs Gave us:
PS: I refer to the circuit designer, not the chip.
Connected and driving, it sure seemed like more! But I think the RthetaJA was about 150. Which meant 'damned hot' even at .36W.
With as little as 4k or so on the 1489 receiver inputs, that was getting near another tenth watt dissipation per connected input at that end, with +/-12-15V signaling applied, too. Part of the spec, sure; but still ...
There was an advantage to all this, I suppose. I could find the 1488 and 1489 parts blindfolded. Just casually feel where the heat is emanating from. ;)
No doubt. I didn't get around to using them until much later, though, being that I was in grade school in the early '60s.
Jon
___
I'm the OP of this thread and would like to thank everyone for such a voluminous and knowledeable response! For those that wanted to know, the chip is the SV2000 video interface chip from
As you can see from the data sheet, the connection on pin 6 allows for either "normal" or "inverted" TTL levels to be used. I think I could have saved lots of confusion by rephrasing my question to: "What's the idling voltage of normal and inverted TTL serial lines?" I can write the program to have the line at pin 3 idle at either 0 or 5 volts, and I had a 50-50 chance of having pin 6 wired correctly. Just lazy again. Sorry if I caused any trouble.
Yeah, they don't know what they missed by never working on the old AP & UPI newswire KSR33 teletypes on a leased loop.
-- Service to my country? Been there, Done that, and I\'ve got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
Or the models 14, 15 and 19 that were even before your time. They seemed hi-tech at the time. My first one at home was a 14 with the range crank on top, front. It came from a Telco Toll office.
On Sat, 07 Jan 2006 07:35:18 -0800, Don Bowey Gave us:
Well... take a bow.
33's were uppercase ASCII. I think the wire services used 5 bit machines. The ones with the type box were 28s. I think the 5 bit code corncob machine was the 32.
Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)
I had a model 15 of my own, (Found at a Dayton hamfest) but I used the KSR33 a lot more. We had two of them at the military radio & TV station I worked at in '73 & '74. They replaced our very worn out Kleinschmidts. :-) Later on I had a Metrodata computer with two 20 mA boards for AP & UPI news wires at a United Video Cablevision CATV headend in Cincinatti, Ohio. I was troubleshooting one of the six channel Metrodata graphics computers when I found a couple undocumented commands. One that let me interrupt the 20 mA loop. The other let me type and send messages on a "Read only" system. It wasn't long after that that the hardwire 20 mA loops were replaced with receive only sat equipment.
-- Service to my country? Been there, Done that, and I\'ve got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
We would have been better off with 28:30 of TTY SFX. :-)
I just heard a radio spot the other day with TTY SFX in the background and the announcer using his best "radio announcer" voice (a parody on news-flash style). It was interesting that the sound of the old TTYs is so anacronistic these days.
I was a college freshman running the college radio station solo when they made the mistake and sent the REAL missle attack message over the wire (instead of the regular sunday- morning test tape). That gave us a morning of excitement.
The wire services used 5 bit machines, such as the model 15, 19, and 28. The model 15 is what all of us old fogies remember as the intro to US nightly TV news. They always started and ended with a few seconds of model 15 teletype chatter... Walter Cronkite would fill in the time in between.
The model 32 was a baudot (5 bit) version of the model 33 ascii machine. It was designed for extremely light duty use, such as a small business would need for Telex duty. For those that don't know, or remember, Telex was to business in the 1970's what the fax machine was to business in the
80-90's
There are two stories I remember coming across the news wire while I was at work in broadcast stations. the first was about a tower collapse at a station that killed most of the tower crew, and just missed the engineer who dived under one of the old RCA broadcast consoles as the tower came through the roof and landed on the console. The other was the murders of "String Bean" (and his wife Ramona) who was a comic on WSM's "Grand Ole Opry". they were robbed and murdered in their front yard because he was known to carry a lot of cash on him, due to his mistrust of banks.
-- Service to my country? Been there, Done that, and I\'ve got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida
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