Connecting 2 PCs modem-to-modem

  • Thread starter David Nebenzahl
  • Start date
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David Nebenzahl

Guest
I know it can be done, but am having trouble making it work.

The idea is to connect 2 PCs directly through their modems. Not cable
modems, ordinary 56K modems. I call it my "Poor Man's Network".

I've found the following pages that describe this operation:

http://phorums.com.au/archive/index.php/t-120530.html
http://www.jagshouse.com/modem.html

That second link suggests powering the connecting line with ~24 VDC, but
I don't think that's actually necessary. (The first link describes
connecting two computeri via modem with no extra hardware needed.)

So when I set this up--2 computeri with connected modems, using
HyperTerminal at each end, with the following commands:

o sending computer: ATX3D
o receiving computer: ATA

I hear stuff through the speaker on the RX end, typical modem connect
tones to start, but I don't hear all that "chirping" usually associated
with dial-up connections; just a steady, low tone that lasts for, say,
30 seconds or so, then the connection goes dead and I get "NO CARRIER"
at both ends.

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?

Please don't suggest using Ethernet or something else instead. I'm
trying to use what's at hand here.

Thanks for any help.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
 
David Nebenzahl wrote:
I know it can be done, but am having trouble making it work.

The idea is to connect 2 PCs directly through their modems. Not cable
modems, ordinary 56K modems. I call it my "Poor Man's Network".

I've found the following pages that describe this operation:

http://phorums.com.au/archive/index.php/t-120530.html
http://www.jagshouse.com/modem.html

That second link suggests powering the connecting line with ~24 VDC, but
I don't think that's actually necessary. (The first link describes
connecting two computeri via modem with no extra hardware needed.)

So when I set this up--2 computeri with connected modems, using
HyperTerminal at each end, with the following commands:

o sending computer: ATX3D
o receiving computer: ATA

I hear stuff through the speaker on the RX end, typical modem connect
tones to start, but I don't hear all that "chirping" usually associated
with dial-up connections; just a steady, low tone that lasts for, say,
30 seconds or so, then the connection goes dead and I get "NO CARRIER"
at both ends.

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?

Please don't suggest using Ethernet or something else instead. I'm
trying to use what's at hand here.

Thanks for any help.


Do you have to use a modem?
Click to expand...
Ditch the modems and use a null-modem swizzle cable to connect the RS232
ports.
If you have a parallel port, you can use the trialware version of
totalcommander and the companion program lptdos to connect using
a laplink (swizzle cable) on the parallel ports.
www.pinouts.ru
MUCH faster.
Nice thing about that is you can boot a dos floppy and do file
transfers from your windows machine to load a computer from scratch.

But lan cards wired or wireless are dirt cheap these days.
Drop by my place and I'll GIVE you two...if I haven't pitched them all
by now.
OOps, I didn't say that...'cause you don't want to know.
 
David Nebenzahl wrote:
Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?
Click to expand...
The maximun speed you should set for is 33.6 kbps analogue.

Above that, the communication relies on connection to an ISP's modem
rack port supporting digital network signalling, something that is
missing on your back-to-back attempt.

--
Adrian C
 
On 1/2/2010 4:37 PM Adrian C spake thus:

David Nebenzahl wrote:

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?

The maximun speed you should set for is 33.6 kbps analogue.

Above that, the communication relies on connection to an ISP's modem
rack port supporting digital network signalling, something that is
missing on your back-to-back attempt.
Click to expand...
Thanks. I bumped the speed down to 19,200 (I think*); the sounds were
different, but still no success.

Couple questions:

1. Are the sounds one hears on the RX side those of the sending modem,
the RX one or both?

2. * Hard to tell with HyperTerminal what speed is actually being used.
I configured to modem to use a maximum speed of 19,200, but HT still
said "112xxx" (forget the exact #s) until I went and re-configured the
modem, at which time it then said 19200.

This really should work.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
 
On Sat, 02 Jan 2010 16:20:44 -0800, David Nebenzahl wrote:
I know it can be done, but am having trouble making it work.

The idea is to connect 2 PCs directly through their modems. Not cable
modems, ordinary 56K modems. I call it my "Poor Man's Network".
Click to expand...
Whoa! This brings back memories! Several hundred years ago -- back in
the DOS 5.0/6.0 and Windows 3.1 days -- we ran The $25 Network in our
SOHO. It used the serial ports on the machines for their connection.
IIRC, the drives on all the other machines appeared as 'extra' drive
letters on each machine, and a common printer could be shared, as well.

I'd be surprised to find that software sourced anywhere... (I might
have it on either a 5 1/4" or 3.5" disk in one of the lower stratums of
a basement closet.)
Then again, this might be that piece of sotware:

http://www.funkymonkey.ie/file-archive.html?func=fileinfo&id=117

Another, undated, web page makes reference to the $25 Network. And,
straining my failing memory, the address listed seems Very Familiar:

http://www.jamesroe.com/astro/$25net.htm

All it took was the DOS-based program and an RS-232 cable you could
cobble up yourself.

gl & hny
Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
* Killfiling google & XXXXbanter.com: jonz.net/ng.htm
 
Needing a Supply Voltage may be necessary depending on the type of modems
you are using.
There are some models that give out enough voltage by themselves, and then
there are others that need the extra boost.

Here is a good link for what u are trying to do (it refers to linking a fax
and modem, but will work the same for 2 modems
http://www.epanorama.net/documents/telecom/fax_to_modem.html


Regards
Peter



--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
David Nebenzahl wrote:
On 1/2/2010 4:37 PM Adrian C spake thus:

David Nebenzahl wrote:

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?

The maximun speed you should set for is 33.6 kbps analogue.

Above that, the communication relies on connection to an ISP's modem
rack port supporting digital network signalling, something that is
missing on your back-to-back attempt.

Thanks. I bumped the speed down to 19,200 (I think*); the sounds were
different, but still no success.

Couple questions:

1. Are the sounds one hears on the RX side those of the sending modem,
the RX one or both?

2. * Hard to tell with HyperTerminal what speed is actually being used.
I configured to modem to use a maximum speed of 19,200, but HT still
said "112xxx" (forget the exact #s) until I went and re-configured the
modem, at which time it then said 19200.

This really should work.
Click to expand...

Both modems are set for the same mode. One has to be switched so you
have 'Answer' & 'Originate' modes.

http://hw-server.com/docs/atcommset.html lists some of the commands
in the old Hayes compatible series.

Some early terminal programs set up the modem for you. Some people
just used a freeware 'Bulletin Board' program to get around the problem.

As far as the DC voltage, some modems don't have the telephone line
transformer. They use a set of diodes instead. These need enough
voltage to forward bias them, but it has to be current limited to a few
mA to prevent damage. The DC voltage on a phone line is listed as -48
volts nominal and referenced to ground, but if you were close to the
older type central office it was in the low to mid 50 volt range.

You can also use 'Direct Cable Connection' for serial or parallel
connection of two computers. The cables are easy to make, and a lot
faster than using modems.

Open 'help' in the windows start menu and type cable into the search
box for information. I used to use the parallel port version in Dos and
Win 3.1 days to install software on some computers. That way I didn't
have to install, then remove a CD-ROM drive to install the OS and
drivers. It was also useful to run OEM drive software to repair screwed
up drives after people tried to do Win 95 installs and messed up the low
level format.

Another approach is an external drive enclosure with a USB
interface. Pull the one drive and slave it to the other computer.


The simplest though, is a pair of $10 network cards and a ethernet
cable.

--
Greed is the root of all eBay.
 
There are a number of pc-pc connection programs; I use PCanywhere:
http://www.symantec.com/norton/symantec-pcanywhere
Much cheaper if you shop around.
JR


On Sat, 02 Jan 2010 16:20:44 -0800, David Nebenzahl
<nobody@but.us.chickens> wrote:

I know it can be done, but am having trouble making it work.

The idea is to connect 2 PCs directly through their modems. Not cable
modems, ordinary 56K modems. I call it my "Poor Man's Network".

I've found the following pages that describe this operation:

http://phorums.com.au/archive/index.php/t-120530.html
http://www.jagshouse.com/modem.html

That second link suggests powering the connecting line with ~24 VDC, but
I don't think that's actually necessary. (The first link describes
connecting two computeri via modem with no extra hardware needed.)

So when I set this up--2 computeri with connected modems, using
HyperTerminal at each end, with the following commands:

o sending computer: ATX3D
o receiving computer: ATA

I hear stuff through the speaker on the RX end, typical modem connect
tones to start, but I don't hear all that "chirping" usually associated
with dial-up connections; just a steady, low tone that lasts for, say,
30 seconds or so, then the connection goes dead and I get "NO CARRIER"
at both ends.

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?

Please don't suggest using Ethernet or something else instead. I'm
trying to use what's at hand here.

Thanks for any help.
HOME PAGE:
Click to expand...
http://www.seanet.com/~jasonrnorth
--------------------------------------------------
 
On Sat, 02 Jan 2010 16:20:44 -0800, David Nebenzahl
<nobody@but.us.chickens> put finger to keyboard and composed:

I know it can be done, but am having trouble making it work.

The idea is to connect 2 PCs directly through their modems. Not cable
modems, ordinary 56K modems. I call it my "Poor Man's Network".

I've found the following pages that describe this operation:

http://phorums.com.au/archive/index.php/t-120530.html
http://www.jagshouse.com/modem.html

That second link suggests powering the connecting line with ~24 VDC, but
I don't think that's actually necessary. (The first link describes
connecting two computeri via modem with no extra hardware needed.)

So when I set this up--2 computeri with connected modems, using
HyperTerminal at each end, with the following commands:

o sending computer: ATX3D
o receiving computer: ATA

I hear stuff through the speaker on the RX end, typical modem connect
tones to start, but I don't hear all that "chirping" usually associated
with dial-up connections; just a steady, low tone that lasts for, say,
30 seconds or so, then the connection goes dead and I get "NO CARRIER"
at both ends.

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.

So what am I doing wrong here?
Click to expand...
Some modems have a transformer based DAA and electromechanical relay,
others have a silicon DAA. The latter consists of a host side chip and
a line side chip. The line side chip requires loop current to operate.

You can tell whether you have an DAA with a electromechanical relay by
muting the modem's speaker and commanding it to pulse dial (while
disconnected from the phone line).

ATL0M0DP00000000 (all zeros, no "ohs")

Listen for the clicking of relay contacts.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
On 1/2/2010 9:49 PM Michael A. Terrell spake thus:

You can also use 'Direct Cable Connection' for serial or parallel
connection of two computers. The cables are easy to make, and a lot
faster than using modems.
Click to expand...
This turned out to be the best way to get 'er done. Fuck the modems;
turns out I already had the perfect cable in my "box o'snakes", a weird
null-modem cable (by Belkin) with *two* sets of connectors on each end
(DB-9 and DB-25). Was easily able to get things cranked up to 115200 and
xfer files with HyperTerminal.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
 
Sorry for coming in late, but if the computers are in the same room, there's
no need for modems, as there is no need to modulate/demodulate. A simple
serial-port-to-serial-port connection is enough -- with the right software.
 
David Nebenzahl wrote:
On 1/2/2010 9:49 PM Michael A. Terrell spake thus:

You can also use 'Direct Cable Connection' for serial or parallel
connection of two computers. The cables are easy to make, and a lot
faster than using modems.

This turned out to be the best way to get 'er done. Fuck the modems;
turns out I already had the perfect cable in my "box o'snakes", a weird
null-modem cable (by Belkin) with *two* sets of connectors on each end
(DB-9 and DB-25). Was easily able to get things cranked up to 115200 and
xfer files with HyperTerminal.
Click to expand...

Only ONE 'Null Modem' cable? Amateur! ;-)


--
Greed is the root of all eBay.
 
On 3 Gen, 01:20, David Nebenzahl <nob...@but.us.chickens> wrote:
o sending computer: ATX3D
o receiving computer: ATA
Click to expand...
I've done this and it worked for me with two internal winmodems. If
you can see the modem board (as in internal modems) watch for a small
transformer, if the modem does not have one it may not work without
line voltage.

I think it only worked if you issued ATX3D first in one computer and
then ATA in the other within a timeout period.

Everything seems configured correctly: I've set the speed at both ends
to 56K and disabled waiting for dial tone.
Click to expand...
I think you mean the serial port speed here, you can set it to 115000
and it will work. To limit the real modem speed you must use an AT
command but if you don't it will negotiate 33.6k.
 
In article <4b3fe1bc$0$4738$822641b3@news.adtechcomputers.com>, David
Nebenzahl <nobody@but.us.chickens> writes

That second link suggests powering the connecting line with ~24 VDC, but
I don't think that's actually necessary.
Click to expand...
I think that's incorrect. You need to provide some line voltage. 12VDC
will do it.

computeri
Click to expand...
I feel sick.

Please don't suggest using Ethernet or something else instead. I'm
trying to use what's at hand here.
Click to expand...
You must have a cable to connect the modem line jacks together. If it
has at least 3 cores free, why not use a direct serial-serial connection
instead of farting about with modems?

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(") http://imgs.xkcd.com/comics/windows_7.png
 
Mike Tomlinson Inscribed thus:

In article <4b3fe1bc$0$4738$822641b3@news.adtechcomputers.com>, David
Nebenzahl <nobody@but.us.chickens> writes

That second link suggests powering the connecting line with ~24 VDC,
but I don't think that's actually necessary.

I think that's incorrect. You need to provide some line voltage.
12VDC will do it.

computeri

I feel sick.

Please don't suggest using Ethernet or something else instead. I'm
trying to use what's at hand here.

You must have a cable to connect the modem line jacks together. If it
has at least 3 cores free, why not use a direct serial-serial
connection instead of farting about with modems?
Click to expand...
I belive the modem to modem cable needs to be Xover as well.

--
Best Regards:
Baron.
 
On Wed, 06 Jan 2010 13:24:13 +0000, Baron wrote:
Mike Tomlinson Inscribed thus:
Nebenzahl <nobody@but.us.chickens> writes

Please don't suggest using Ethernet or something else instead. I'm
trying to use what's at hand here.

You must have a cable to connect the modem line jacks together. If it
has at least 3 cores free, why not use a direct serial-serial
connection instead of farting about with modems?

I belive the modem to modem cable needs to be Xover as well.
Click to expand...
Google "null modem".

Jonesy
 
On 06/01/2010 15:36, Allodoxaphobia wrote:

Google "null modem".

Jonesy
Click to expand...
Google "This turned out to be the best way to get 'er done" in quotes.

Note the subject title. :-|

--
Adrian C
 
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