Xref: utzoo comp.dcom.modems:4602 sci.electronics:8061 Path: utzoo!attcan!uunet!opel!johnk From: johnk@opel.uu.net (John Kennedy) Newsgroups: comp.dcom.modems,sci.electronics Subject: Anyone have a modem dialing out on two lines? Message-ID: <282@opel.uu.net> Date: 1 Oct 89 22:18:57 GMT Reply-To: johnk@opel.UUCP (John Kennedy) Organization: Second Source, Inc., Annapolis, MD Lines: 41 Got a Telebit Trailblazer+, and two phone lines serving two dialing areas. I'm trying to come up with a scheme that allows me to dial out on either of the two lines. I'm assuming that I'll use some sort of solid state relay, or even a telephone crosspoint chip, but don't know yet how I'll control it. So far, the options I'm considering are: 1) A device driver in the host system that will toggle a lead. This would be actuated just prior to sending the dialing sequence to the modem, and reset at the end of the call. 2) A UART and controller which listens to the AT sequence being sent to the modem, and which switches lines upon detection of a certain AT sequence. 3) A DTMF decoder which listens to an outpulsed sequence from the modem, then connects one of the two lines in time for the delayed, real digits. 4) If I replaced the modem with a Telebit T2000, the option exists to assert the A/A1 leads (second pair) coming out of the modem. Techs at Telebit confirmed that the TB+ does not have this capability. These leads could be used to control the switching. Anyone using these? Option 1 would require the least hardware, but I have a concern about leaving the wrong line connected in case of an aborted dialing attempt. Anyone done anything similar, or have any suggestions? Thanks in advance, John -- John Kennedy johnk@opel.uu.uunet Second Source, Inc. Annapolis, MD