titus@dri0.UUCP (06/09/84)
[.] I have an application where a client of mine needs fast communications from a UNIX(TM) based computer system in Pittsburgh, to a similar machine in Washington D.C. The cost of high speed voice-grade compatible modems is not a problem here, but we are troubled by the fact that the model that we are looking at, a UDS 9600 A/B (9600 baud, synchronous, also using an error correcting async-sync converter) can operate only at half duplex over a two wire line. We have need for both file transfer and remote terminal usage on this line. In case this is relevant, we have been looking at a voice grade private line between the two points, because of the expected traffic. If you have any suggestions for half duplex communications software under UNIX (a binary license, unfortunately) or any other suggestion about a hardware solution to this problem, please either call me, or contact me over the network. Thanx in advance, Bill Titus (412) 562-9662 Decision Resources, Inc. 950 Century Building 130 Seventh Street Pittsburgh, PA 15222 decvax!mcnc!idis!pitt!dri0!titus
husak@itivax.UUCP (06/14/84)
I tried mailing a reply, but our mailer managed to come up with an address that was so long that it couldn't handle it. Good thing too, it looked like it had managed to put several loops into it. Yow. Anyway what I said was, The UDSs will operate either half or full duplex, the latter requiring four wire service. I think you will find that the cost of a four wire circuit is only marginally greater than a two wire one. This is reflective of the fact that internally a long distance facility uses full duplex circuits, so only the local loops are additional. I question the need for error correcting sync-async converters. Hopefully the carrier facilities will be quite enough for terminal use (if not, bitch) and UUCP will detect errors during file transfers.