ddp+@ANDREW.CMU.EDU (Drew Daniel Perkins) (12/01/88)
I was reading looking at the CCITT Red Book "Recommendations of the V Series" (Volume VIII - Fascicle VIII.1) today and noticed an interesting protocol "Recommendation V.25 bis, Automatic Calling and/or Answering Equipment on the GSTN Using the 100-Series Interchange Circuits". This recommendation basically specifies an equivalent of the Hayes "AT" command set for modems. The thing I found most interesting was that it specified it for synchronous links (both bit and character oriented) in addition to async links. Does anyone know of anything that supports this protocol? Is there a good reason why it isn't common? I'm thinking that it might be very usefull for dialing sync modems, dialing ISDN Terminal Adaptors, connecting sync port selectors, etc. Drew
heath@ncrcae.Columbia.NCR.COM (Robert Heath) (12/06/88)
In article <sXZ9Wiy00UoJEHqyws@andrew.cmu.edu> ddp+@ANDREW.CMU.EDU (Drew Daniel Perkins) writes: >I was reading looking at the CCITT Red Book "Recommendations of the V Series" >(Volume VIII - Fascicle VIII.1) today and noticed an interesting protocol >"Recommendation V.25 bis, Automatic Calling and/or Answering Equipment on the >GSTN Using the 100-Series Interchange Circuits". >Does anyone know of >anything that supports this protocol? A number of modem manufacturers such as Anderson-Jacobsen, Concord Data, NEC, etc. support the protocol. The NCR TOWER series supports the v.25bis dialing protocols when you order SDLC/HDLC support. >Is there a good reason why it isn't >common? I'm thinking that it might be very usefull for dialing sync modems, >dialing ISDN Terminal Adaptors, connecting sync port selectors, etc. > One drawback is that the dialing interface occurs at the data link control (DLC) level, which is usually not open to user programming. They introduce some new handshaking at protocol levels which have been frozen for years. In synchronous networks that most open layers are much higher up in the protocol stack. For a full discussion of v.25bis, see my article "Synchronous dialing modems are advancing at full tilt", in the Nov. '87 issue of Data Communications magazine. Robert Heath heath@ncrcae.Columbia.NCR.COM
gnb@melba.bby.oz (Gregory N. Bond) (12/06/88)
In Australia, the Dataplex dpx-224 modem supports the v25bis set.
(At least it's described in the manual. Who knows if it works?)
Greg.
--
Gregory Bond, Burdett Buckeridge & Young Ltd, Melbourne, Australia
Internet: gnb@melba.bby.oz.au non-MX: gnb%melba.bby.oz@uunet.uu.net
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