roy@phri.UUCP (Roy Smith) (08/28/85)
After weeks of trying to get my Vax to autobaud on a dial-in line with a CTS 2424-ADA modem, I've just discovered something horrible. If I call in at 2400 baud, the answer modem correctly answers the call, goes into high speed mode, and everything is fine. If I dial in with a regular 212A modem at 1200 baud, the answer modem answers the call and the two data sets correctly negotiate the 212A protocol between themselves. The problem is that the RS-232 side of the answering unit remains at 2400 baud. This certainly does make the auto-baud stuff easy (i.e. just run at 2400 baud all the time). On the other hand you no longer have any way of knowing the *real* speed of the line in cps; you loose big if you are doing anything that can't deal with XON/XOFF flow control (like emacs). Here you are throwing 240 cps down a 120 cps channel; something has got to give somewhere. Does anybody know how to make the CTS-2424 adjust the baud rate on the RS-232 port to match the modem-to-modem link? If not, does anybody know of any other modems that do this the "right" way? I would guess that in theory this a problem without a real answer; a V.22bis link is always free to drop back to 1200 baud (or even further?) in the middle of a call if the line conditions demand it. In all fairness, this is a nice feature if you have the modem attached to a terminal used to call several systems, some with V.22bis lines, some with just 212A lines. You never have to fiddle with baud rates at all and at the terminal end there is no problem with flow control (unless you can type more than 500 wpm). However, if there is no way to turn it off, it just doesn't work on a dial-in port. -- Roy Smith <allegra!phri!roy> System Administrator, Public Health Research Institute 455 First Avenue, New York, NY 10016