perry@haven.umd.edu (Guru's Inc.) (12/02/89)
>From article <telecom-v09i0533m05@chinacat.lonestar.org>, by cmoore@brl.mil > [Moderator's Note: I am still curious to find out the use of 710. This > one is listed with the cryptic notation 'special goverment services' > or 'government special services' with no further information posted in > the listings of same. Does anyone have any ideas? PT] This reply to PT on use of 710 "area code" (Warantee: The following fine details from remote memory not CRC protected!) Back in the 70's when Western Union Telex was growing and AT&T agreed to sell their TWX system to Western Union I remember the 710 and 810 codes were used by the TWX teletypes. At that time twenty years ago there were two different teletype exchanges. WU Telex, a 5-bit (baudot code) 3 row teletype machine runing at 75 baud, (100wpm) over 20 millampere dc legs toward the telex switch. Of course, 20 75 baud circuits could be muxed onto a single VF circuit. Mechanical 202 relays (20mil to 60mil interface to type 60 and 70 carrier equipment (FSK)) were becoming solid state in 1969. Our telex machine in Hawaii was served by the Oakland Calif. switch. WU computers were being used to store and forward telex traffic between these two systems. The WU Telex machine had a rotary dial and 4 lighted pushbuttons, "Start; Dial; Connect; Disconnect." Numbering plan was variable length. 05xxxx, 098xxxx etc. DA was 018. You pressed Start and Dial would light if the switch answered, then you dialed the number. If the remote machine answered, Connect came on, the motor started and answer backs were exchanged. If not Disconnect occured. After sending text from either keyboard or from punched paper tape you pushed Disconnect when finished. The Bell System TWX machines were ascii code 4 row machines and also they had 3 row baudot ones that ran at a slightly different rate from the WU ones. Within Bell these two different teletypes talked to each other thru code and speed converters in the TWX CO. The 4 row keyboard machine also had a dial unit with a half of a handset, just a receiver. These machines when you pushed a start button went off hook with dial tone. You dialed a 10 digit number. The receive was so you could hear the state of call progress, (sorry wrong number.. etc..) 710-xxx-xxxx was the slower speed network, 810-xxx-xxxx the ascii other speed network. The TWX machines used the telephone network for switching, and by nature each teletype call used a VF switched trunk. Now 710 and 810 could not be called from any regular phone, only from TWX. A 710 machine could DDD any other 710 machine on the same or another switch. The same for an 810 machine to another 810 machine. I can still see vividly the Bell description and diagrams on the TWX exchange. For a 710 machine to talk to an 810 machine or vice versa, on another switch or the same switch the codes 710 or 810 were flipped to signal code conversion equipment required. i.e. 017, or 018. The codes may pass thru more than one switch to the destination CO. The destination switch made the speed change, flipped the codes 017 / 018 back over to 710 / 810 for normal number processing. IF the destination number was on the same switch, that switch called out on special trunks back to itself thru the code/speed exchanger equipment. When WU aquired TWX from Bell, WU intergrated it into the Telex network with a main computer in Mawah NJ. Did the speed/code conversion, provided store and forward services, international interfacing. Infomaster Services came out of Middletown Va. One could book a single message to multiple addresses. And that's the way I remember it so long ago ___ [Perry Mathis, Centel Federal Systems, 11400 Commerce Park Dr. Reston Va. 22091 703 758-7000 ]
joe@mojave.ati.com (Joe Talbot) (12/04/89)
I used to work for a radio station in Orange County that had a TWX machine. We used it to get orders from ad agencies and to add or "pull" music from the playlist (we were programmed by someone from another area). When I first started there (november 1978) the TWX machine's dial tone came from Pacific Telephone (from the Anaheim Lemon street crossbar). The, one day, it changed! The dial tone level was lower, and the service came from an electronic switch. The switch wouldn't allow the use of pulse dialing, probably because the machine we used normally was a tone machine (model 33, yecch). joe@mojave I finally changed my dumb signiture. People were always telling me what a great signature I had.