Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!cmcl2!rutgers!ucla-cs!zen!ucbvax!BLUTO.SCC.COM!enger%gburg.DECnet From: enger%gburg.DECnet@BLUTO.SCC.COM ("GBURG::ENGER") Newsgroups: comp.protocols.tcp-ip Subject: DSU/CSU units Message-ID: <8709221709.AA08289@ucbvax.Berkeley.EDU> Date: Tue, 22-Sep-87 13:33:00 EDT Article-I.D.: ucbvax.8709221709.AA08289 Posted: Tue Sep 22 13:33:00 1987 Date-Received: Thu, 24-Sep-87 05:38:09 EDT Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: "GBURG::ENGER" Organization: The ARPA Internet Lines: 39 We have a couple of T1 circuits, but the equipment on the ends functions as its own "DSU", so all that is required are outboard CSU units. We use Digital Link Corp. Model 551C. I think we have had three blow out so far. And a fourth leaked span power to its chasis! It turns out they had problems with the physical construction of the units. A bolt came very close to the circuit board and often shorted or arcked during electrical storms, etc. The factory supposedly installed an engineering modification (cutting the excess off of the bolts probably) to lower the likelyhood of lightning damage. When one of the units came back from getting "the fix", its Percent Error Free Seconds display simply counted down constantly. The Error Free seconds display is a nice feature. It keeps an "objective" eye on the status of the line. Makes it real easy to point the finger at the phone company. Other than span power outages due to lightning blowing the CO fuses, the only problem I have ever had with the T1s was a bad punch at the undergroud, and the CSU EFS display showed it as an excessive error rate, and indicated which direction the problem was in. The local operating company fixed it promptly, no questions asked. They took one look at the display on the csu, and went to work on the span. If you wish to contact them, Digital Link is in Sunnyvale, Ca Phone number 408-745-6200 Good luck, bob From: GBURG::ENGER "Robert M. Enger {CONTEL Fed. Sys} (301)840-4906" 22-SEP-1987 12:42 To: GBURG::MAILER,ENGER Subj: RE: [TCP/IP Mail From: ] ludwig non-functional when net is down I don't "think" the ypbind has anything to do with the iebark reset. I'll check into it. bob (I think rebooting the machine is what cleared your problem??) bob ------