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- Message-ID: <1993Jan11.072613.80887@laison.w8hd.org>
- Newsgroups: comp.sys.mac.hardware
- Distribution: world
- From: jimh@laison.w8hd.org (Jim Hebert)
- Organization: L'AISON - Local Area Information Server Open Network
- Date: Mon, 11 Jan 1993 07:26:13 EDT
- Subject: Re: Modem cable myths
- Lines: 40
-
- scasterg@waltham.columbus.oh.us writes regarding hardware "handshaking":
-
- > This is important to know if you are using a
- > Mac Plus, Classic and a couple other models
- > (LC?) which will simply not support hardware
- > handshaking due to braindead design.
-
- If we are trying to clear up myths, then let's clear up the two created by
- this sentence:
- What the Plus lacks is the serial port's pin-7 connection, used on other Macs
- for connecting to the modem's DataCarrierDetect output. This is nice to have
- if you are running a host system, since it provides a way to determine (via
- hardware) if a caller has hung up, but it is totally unnecessary for
- implementing flow-control. The GPI connection is missing from the Mac Plus,
- Mac Classic, Mac Classic II, Mac LC, and Mac LC II.
-
- > Finally, a reliable source for hardware
- > handshaking cables: Mac Dataflow (410)
- > 569-7636 Just ask for "cable ID 3 from the
- > Hermes docs."
-
- I am not familiar with what wiring results from following "cable ID 3 from the
- Hermes doc". ( But it sure sounds like the kind of stuff myths are made of!)
- Before pointing people in that direction I think one ought to specify what
- connections one gets from this arrangement. Cables wired for hardware flow
- control are quite abundant these days. What is harder to find is cables that
- contain wiring from the modem connector's pin 8 (DCD) to the mac's pin 7
- (GPI). But not many people need that connection in their cable. (Of course,
- if you do have such a cable, you need software that will pay attention to the
- status of the DCD; to my knowledge, there isn't any Mac comm software that
- does. One exception to this is the Server software of FirstClass. It has an
- option for using DCD via mac pin 7 to monitor the status of the modem
- carrier.)
-
-
-
- _____________________________________________________________________________
- Jim Hebert L'AISON = Local Area Information Server Open Network
- jimh@laison.w8hd.org Tel: 313/647-2634 Beverly Hills, Michigan
- ______________________________________________________________________________
-