Everhart, Glenn From: reece@eco.twg.com Sent: Wednesday, March 10, 1999 11:26 AM To: Info-VAX@Mvb.Saic.Com Subject: Re: Re[2]: Dial-in modem on OPA1 on Alphastation 255 On Tue, 9 Mar 1999 17:00:32 -0600, WILLIAM WEBB wrote: > >In article <7c1abt$9g1$1@uranium.btinternet.com>, "Robin Mann" > writes: > When I try to dial-in to a US Robotics >modem on OPA1 on an Alphastation 255 >> running VMS 6.2, I get a message about the modem not being wired correctly. >> OPA1 is 9-pin. The Alpha manual says it supports full modem control. Can I >> not use a standard modem cable? > >I'e been wrong before, but I thought it took at least 12 pins to get fumm >modem control. It just can't be done on a 9 pin connector, or an MMJ for >that matter. > > Bob Kaplow > >SPAM: uce@ftc.gov postmaster@127.0.0.1 otherwise, I'm not on MARS! > > Uh, Bob, what about good old 1 through 8 and 20? That's nine lines... Full modem control can be done with 9 lines, but you're ever so slightly off on which ones you need from the DB-25: DB-25 DB-9 Signal ----- ---- ---------------------- 2 3 TxD - Transmit data 3 2 RxD - Receive data 4 7 RTS - Request to Send 5 8 CTS - Clear to Send 6 6 DSR - Data Set Ready 7 5 SG - Signal Ground 8 1 DCD - Data Carrier Detect 20 4 DTR - Data Terminal Ready 22 9 RI - Ring Indicate The DB-25 pin 1 is frame or shield ground, and isn't critical. It should only be connected on one end anyway, and it can be connected through the connector shell and screws. -- Reece R. Pollack Senior Software Engineer Attachmate Specialty Products Group