[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: ProTERM
In article <3n8jp7$aso@bmerhc5e.bnr.ca>,
Jeffrey Robertson <jeffr@bnr.ca> wrote:
>
> As it happens, I'm running SnowTerm. Can it not handle 9600? The
> configuration screens certainly talk about faster speeds.
I suspect that SnowTerm will not support hardware handshaking. Most
older communications programs don't.
You should be able to use 9600 without any problems, but that will be
WITHOUT error correction or data compression. If you want to go
faster and/or use correction/compression, you must use a higher port
speed (e.g. 19200) and use hardware handshaking.
It all depends on whether the program supports hardware handshaking.
On a IIgs, the serial firmware will be used by most of the simple
comms programs (e.g. ZLink, TIC, FreeTerm and probably SnowTerm). The
IIgs firmware _does_ support hardware handshaking (set "DSR/DTR
Handshake" to On), but many programs ignore and/or override the
control panel settings, or do not use the outgoing handshake line
correctly.
The other handshaking options in the Control Panel (XON/XOFF and DCD)
should be disabled.
A hardware handshaking cable for the IIgs is wired as follows:
IIgs (Mini-Din-8) Modem (DB-25 male)
1 Handshake Out ------------- 4 RTS (optionally also pin 20, DTR)
2 Handshake In ------------- 5 CTS
3 TxD minus ------------- 2 TxD
4 Ground ------------- 7 Ground
5 RxD minus ------------- 3 RxD
6 TxD plus no connection
7 Carrier Detect ------------- 8 DCD
8 RxD plus connect to ground (pin 4 at IIgs or pin 7 at modem)
Looking at the back of the IIgs, the serial port pins are numbered:
8 7 6
5 4 3
2 1
Regarding the outgoing handshake line: the connection to the RTS pin
is required for hardware handshaking. The connection to the DTR pin
is optional. If connected, this allows the IIgs's handshake output to
be used by normal communications software to hang up a call.
For hardware handshaking operation, the modem must be told to ignore
the DTR signal (AT&D0) and to use hardware handshaking (the command
varies, AT&K3 is common).
For non-handshaking operation, the modem must be told to not use
hardware hanshaking (the command varies, AT&K0 is common) and AT&D2
may then be used to force the modem to hang up if DTR is dropped.
The carrier detect signal is not specifically required for hardware
handshaking, but is used by many comms programs to detect whether the
modem has established (or lost) a connection. On some modems, this
signal will be always on by default, and a true carrier detect
indication can be enabled by using the AT&C1 command.
--
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand