7 May
2008
7 May
'08
2:23 a.m.
-------------Original Message:
Date: Tue, 6 May 2008 23:27:13 +0100 (BST)
From: ard at p850ug1.demon.co.uk (Tony Duell)
Subject: Re: Interconnecting classic computers
Has anybody ever tried interfacing a modem to a cordless phone handset?
Are cordless phones truely full-duplex, or are they more like
loudspeaking phones whee a local voice input disables the speaker output?
That is not a problem for voice, of course, but it is for full-duplex modems.
It shouldn't be too hard to use a C/L phone as the
wireless link between two
modems.
I believe Tony also has a NetCommander which would let him select which
Actually I have 3 of them. One is the 16 port model (with 16 RS232
ports), the others are the fixed-configuration 6 RS232/4 Centronics models.
But they do not solce the cabling problem. Nor do they have enough ports
for all my classics...
-tony
-----------Reply:
Well, that gives you 25 ports; how many more do ya need? At one point we
had 4 computer ports feeding more than 200 terminals over a single connection.
Alternately, it would be trivial to build a remotely controlled one-to-many port
selector out of relays or solid state parts, and you could use the NetCommander
just for the units that need baud rate conversion.
Of course the NCs don't solve the cabling problem, that's why I mentioned the
cordless phone. But unless you want to manually plug the desired system in
every time or buy/make separate connecting links for every system, you'd
need some way of concentrating the systems into one connecting link.
Obviously not a solution you'd approve of, but two old laptops with RS-232
and wireless cards would easily solve the connection problem. Of course
we usually prefer lengthy discussions here instead of simple solutions...
mike
7 May
7 May
9 p.m.
I believe Tony
also has a NetCommander which would let him select which
Actually I have 3 of them. One is the 16 port model (with 16 RS232
ports), the others are the fixed-configuration 6 RS232/4 Centronics models.
But they do not solce the cabling problem. Nor do they have enough ports
for all my classics...
-----------Reply:
Well, that gives you 25 ports; how many more do ya need? At one point we had 4 computer ports feeding more than 200 terminals
over a single connection.
Alternately, it would be trivial to build a remotely controlled one-to-many port
One-to-many is easy, many-to-many is slightly harder, and the latter is
what I would need. I am not looking to interconenct one of my classics to
this PC, I am looking to interconnect any pair of my classics
selector out of relays or solid state parts, and you
could use the NetCommander
just for the units that need baud rate conversion.
Of course the NCs don't solve the cabling problem, that's why I mentioned the
And cabling is what I am primarily interested in.
cordless phone. But unless you want to manually plug
the desired system in
every time or buy/make separate connecting links for every system, you'd
Given that I can't have lal the machines et up at the same time, there
has to be some plugging/unplugging going on. Doing that is not a problem
(nor do I object ot wiring up adapters for each of my machines to get the
RxD and TxD on a consistent pair of pins in all cases, to loop back
handshakes, and so on).
need some way of concentrating the systems into one
connecting link.
Ture enough.
Obviously not a solution you'd approve of, but two old laptops with RS-232
Round here 'old laptops' are things like Epson HX20s, PX4s, PX8s, Tandy
Model 100s, Olivetti M10s, HP110s, HP110+s and so on. Rahter _too_ old
for this :-)
and wireless cards would easily solve the connection
problem. Of course
we usually prefer lengthy discussions here instead of simple solutions...
But is it a simple solution? I suspect I would find it quicker and
easier to make a PSU and RS232 buffers for an Xbee module (and hope I can
either ignore hardware handshaking or use it with machines that support
it [1]) than to figure out how to configure the software on oen of said
laptops.
[1] Which, alas, excludes my DEC PDP8 and PDP11 machines :-(
-tony
17 May
17 May
8:51 a.m.
On Wed, 2008-05-07 at 22:00 +0100, Tony Duell wrote:
One-to-many is easy, many-to-many is slightly harder,
and the latter is
what I would need. I am not looking to interconenct one of my classics to
this PC, I am looking to interconnect any pair of my classics
Just a thought, but can you live with just TXD, RXD and ground? If you
can, then make a bunch of serial-to-1/4" jack cables, and buy a cheap
studio patchbay. They consist of a row of little boards with four 1/4"
stereo jacks on them, wired so that normally two are wired together,
plugging into one socket breaks the link, and plugging into the other
socket parallels with the two on the back.
Gordon
6069
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