EVERHART%ARISIA@rca.COM ("GLENN EVERHART, 609 486 6328") (05/29/87)
The cycling of DTR in DEC operating systems is not a bug but a feature... If it is not done, a random call can tie up the phone line for some time (depends on the phone company HOW long but in some places it seems to be practically forever) and thus deny system access even where the line was dialed by mistake. The system attempts to correct this by toggling DTR off once in a while, but leaving it on when the modem senses carrier. While this creates small time windows when a modem will not answer the phone, it also keeps the phone lines on an idle modem also free. I may have garbled part of this explanation (it's been 6 or 8 years since I read it) but the intent really is to adapt to some weird behaviour that some phone systems have. If I did garble it and someone with a clearer memory of the problem can enlighten us all, please do so. Glenn Everhart everhart%Arisia@rca.com