pat@tifsil.UUCP (Pat Peters) (02/08/88)
Background: We're running Ultrix 2.0 on a MicroVAX II. We've got Hayes Smartmodems (1200 baud). We use the generic dialer of tip and uucp. Recently, we moved our computers some distance away from their former location. Ungermann-Bass NIUs are now used for terminal connectivity. Phone requests take forever to get done, so we figured on connecting our modem via a permanent circuit on the NIUs (For those of you not familiar with the NIUs, the are Ethernet based terminal servers. The permanent circuit fixes it so the same two NIU ports always and forever find each other and, therefore, the computer and the modem shouldn't know the NIU is even there). Problem: tip was hanging up the phone the minute the modem connected to the other side. Studying the source revealed the cause: the very moment that carrier detect is signalled, the generic dialing routines attempt to read the sync string. There is NO DELAY before doing the first read. If there is no character there when the read is done, the dialer aborts. Apparently the time lag caused by the NIU (so short to be unnoticed by human terminal users) is long enough to upset the dialer. I have not tried the generic dialer in uucp, but it is common code with tip so I hold little hope it will work better. Work around: I've set up the modems as DIR lines instead of ACUs and I now talk to the modem myself. It works, but I prefer to use the dialer-- it instigates a hangup at the end of the conversation instead of sitting at the mercy of the other end. Comments? Suggestions? Thanks! -- Patrick Peters UUCP: ut-sally!im4u!ti-csl!tifsie!pat Texas Instruments sun!texsun!ti-csl!tifsie!pat PO Box 655012 M/S 3635 uiucdcs!convex!smu!tifsie!pat Dallas, TX 75265 Voice: (214)995-2786