lauren@vortex.UUCP (Lauren Weinstein) (05/28/83)
Greetings. Sorry to send this message to two groups, but I felt that it should have as broad a distribution as possible. I've been watching UUCP dialup patterns on several sites (including vortex) and am beginning to suspect that some (many?) sites are using too SHORT an interval for their dialing timeout for calling other sites. I've noticed a pattern of some sites that ring once and then immediately hang up, or which hang up *immediately* after getting carrier (before ACU transfer to the modem could be completed, essentially). I believe that the issue here is an underestimate of the time required to establish a connection to some sites. Remember that there are a variety of factors that can effect call setup time. If you are calling a site on a step-by-step telephone exchange, the connection interval can be greatly increased. The same goes for numbers on Direct Inward Dialing Trunks which are using pulse dialing (there are lots of these still around and still being installed!) Note that I am talking about the site you are CALLING in both cases -- not the site making the call. Another important factor is that many modems (including Bell 212A's) require a FULL RING before they will answer. If you happen to partially ring the line when you first connect, there will be a full inter-ring pause and another ring before the modem answers, and a bit more delay before carrier is sent by the answering modem and detected by the originating modem. The upshot of all this is that, I believe, a more liberal timeout interval could help decrease the number of "almost connects", which might be wasting a substantial amount of time. Nobody really knows, of course, since most sites do not and cannot log such events (since the answering modem never realized a call came in, and the originating modem would assume a "no-answer" or "busy" situation.) I would recommend a full 45 second timeout after dialing has completed for all long distance calls to help avoid these problems. Depending upon your ACU arrangement, you may be able to force a longer interval by putting some dialing "pauses" into your L.sys line for the appropriate sites (this will not work with some ACU's, so be careful.) Others may have to change the actual interval inside UUCP, but I expect this would be fairly rare. I believe that many people have already "played around" with the timeout interval, possibly even to SHORTEN it, judging from some of my observations. Just because a short interval works for MOST calls, it doesn't mean that it'll work for ALL calls! Thanks much. --Lauren--