Path: utzoo!telecom-request Date: Tue, 4 Jun 91 11:50:27 CDT From: u1906ad@unx.ucc.okstate.edu Newsgroups: comp.dcom.telecom Subject: Re: Rotary Dial Phones Forgotten But Not Gone Message-ID: Organization: TELECOM Digest Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 425, Message 11 of 15 Lines: 33 brian@ucsd.edu (Brian Kantor) writes: > Ken Oberman wondered when COs would stop supporting pulse-dial > (rotary) phones. Well, PBX's already have; the UCSD Ericsson MD-110 > will not allow an extension phone to pulse-dial any number with a "1" > (one) in it -- it interprets the single pulse as a switchhook flash and > gives you a fresh dialtone. Oklahoma State University has had an Ericsson MD110 switch in use since Fall of 1988. It is a truly digital PBX with the vast majority of campus phones having A/D D/A converters in their bases. While I've been told that the signal on each wire pair is proprietary, it is pretty close to ISDN. Such indications as on-hook, off-hook, ring and caller id information are all just digital codes sent on the control channel. The situation that Bryan described regarding getting a fresh dial tone each time the hook was flashed sounds precisely like what happens when you flash the hook on an Ericsson digital phone. Ericssen also makes an analog line card which plugs into the MD110 switch so as to support such things as fax machines and the radio paging system operated by our physical plant. The analog line unit provides all of the standard telephone signals and will accept either pulse or tone dialing. The best way to tell what kind of Ericsson line one is on is to listen to the sound of the line as you dial a number. On a digital line, there is absolutely nothing heard between the dial tone and the first ring. Martin McCormick Amateur Radio WB5AGZ Oklahoma State University Computer Center Data Communication sGroup Stillwater, OK