Article 1958 of comp.sys.apple2.comm: Newsgroups: comp.sys.apple2.comm Path: winternet.com!interlog.com!news1.fonorola.net!newsjunkie.ans.net!howland.reston.ans.net!cs.utexas.edu!news.sprintlink.net!uunet!in1.uu.net!comp.vuw.ac.nz!actrix.gen.nz!dempson From: dempson@atlantis.actrix.gen.nz (David Empson) Subject: Re: GS + Proterm + 14.4 modem (?) Message-ID: Sender: news@actrix.gen.nz (News Administrator) Organization: Actrix Information Exchange Date: Sun, 9 Apr 1995 07:15:40 GMT References: <3lkkds$rdu@news.ysu.edu> <3m4tpq$pcn@blackice.winternet.com> X-Nntp-Posting-Host: atlantis.actrix.gen.nz Lines: 37 In article <3m4tpq$pcn@blackice.winternet.com>, Peter Handel wrote: > > ------------------------------------------ > All you need for a GS/MAC to a HI-SPEED MODEM (using RTS/CTS) is as follows: > ------------------------------------------ > > GS PORT CONNECTOR RS-232C CONNECTOR > (Male mini-8) (Male DB-25) > ----------------- ---------------- > Pin 1: HSKo ------------------> Pin 4: RTS GS Drops HSKo to have mdm stop > Pin 2: HSKi <------------------ Pin 5: CTS MDM Drops CTS to have GS stop > Pin 3: TxD- ------------------> Pin 2: TD > Pin 4: SG <-----------------> Pin 7: SG > Pin 5: RxD- <------------------ Pin 3: RD > Pin 6: TxD+ **NO CONNECTION** > Pin 7: GPi <------------------ Pin 8: DCD Carrier Detection using &C1 > Pin 8: RxD+ **NO CONNECTION** (NORMAL CARRIER DETECT!)^^^ This is wrong. Pin 8 at the IIgs end must be connected to signal ground (pin 4 at the IIgs end or pin 7 at the DB-25 end) to correctly balance the receive signal. The IIgs uses RS-422/423, and the positive receive input must be grounded to guarantee the receive voltage being interpreted correctly. > Oh, I reccomend you bridge pin 4 and pin 20 on the modem (DB-25) end. This is a good idea, provided you set the modem up properly. It gives you the option of using the cable without hardware handshaking, and using the output handshake line to drop DTR and force a hangup. For hardware handshaking use, you must use the AT&D0 command to tell the modem to ignore DTR. -- David Empson dempson@actrix.gen.nz Snail mail: P.O. Box 27-103, Wellington, New Zealand