connecting 2 56K modems

Hye,

I would like to make local tests between two machines having a modem
(simulating a RTC connection). Is it possible to connect directly the two
modems each other and try to call a machine with the other one. If so what
have I to do?

Thanks

Simon wrote:

> I would like to make local tests between two machines having a modem
> (simulating a RTC connection). Is it possible to connect directly the two
> modems each other and try to call a machine with the other one. If so what
> have I to do?

I assume you're talking about dial up modems. Many of them can work
together like that. Read the manual for directions. If they can't work
directly together, you'll need a line simulator.

--

(This space intentionally left blank)

James Knott <(E-Mail Removed)> said:
>Simon wrote:
>> I would like to make local tests between two machines having a modem
>> (simulating a RTC connection). Is it possible to connect directly the two
>> modems each other and try to call a machine with the other one.
>
>I assume you're talking about dial up modems. Many of them can work
>together like that. Read the manual for directions. If they can't work
>directly together, you'll need a line simulator.

Actually there's a middle road that should be ok for most cases (if the
modems don't work with just being wired together): provide correct
phone line voltage. Or not necessarily even correct; some modems work
even with huge undervoltages. This should be much easier to arrange
than a full-blown line simulator (providing dial/ringing/busy tones,
etc).

.... and if someone would be so kind as to fill in how the phone line was
supposed to be powered - i.e. what kind of power supply to connect, and
how to connect it; I haven't done this often, and it's quite some time
since the last time playing with these..
--
Wolf a.k.a. Juha Laiho Espoo, Finland
(GC 3.0) GIT d- s+: a C++ ULSH++++$ P++@ L+++ E- W+$@ N++ !K w !O !M V
PS(+) PE Y+ PGP(+) t- 5 !X R !tv b+ !DI D G e+ h---- r+++ y++++
"...cancel my subscription to the resurrection!" (Jim Morrison)

Juha Laiho <(E-Mail Removed)> wrote:
>James Knott <(E-Mail Removed)> said:
>>Simon wrote:
>>> I would like to make local tests between two machines having a modem
>>> (simulating a RTC connection). Is it possible to connect directly the two
>>> modems each other and try to call a machine with the other one.
>>
>>I assume you're talking about dial up modems. Many of them can work
>>together like that. Read the manual for directions. If they can't work
>>directly together, you'll need a line simulator.
>
>Actually there's a middle road that should be ok for most cases (if the
>modems don't work with just being wired together): provide correct
>phone line voltage. Or not necessarily even correct; some modems work
>even with huge undervoltages. This should be much easier to arrange
>than a full-blown line simulator (providing dial/ringing/busy tones,
>etc).
>
>... and if someone would be so kind as to fill in how the phone line was
>supposed to be powered - i.e. what kind of power supply to connect, and
>how to connect it; I haven't done this often, and it's quite some time
>since the last time playing with these..

Offhand I don't know that *any* modem actually requires "phone
line voltage" (actually, it's "loop current"). If you find one
that does, just put a 9v battery in series with the two modems.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) (E-Mail Removed)

molim da mi pomognete instalirati ovu mreznu karticu pod SuSe profesional
9.1. Mislim da je to kernel 2.6.xx ? U uputama uz driver ima naredba koja ne
radi: "gcc -DMODULE -D__KERNEL__ -c rtl8150.c -I%DIR%/include" (bez
navodnika). Stalno mi javlja: no output file!? Driver koji sam dobio uz
karticu je: rtl8150.c! Hvala svima!

On Thu, 21 Oct 2004 23:35:03 +0200, pionir_maleni wrote:
> molim da mi pomognete instalirati ovu mreznu karticu pod SuSe profesional
> 9.1. Mislim da je to kernel 2.6.xx ? U uputama uz driver ima naredba koja ne
> radi: "gcc -DMODULE -D__KERNEL__ -c rtl8150.c -I%DIR%/include" (bez
> navodnika). Stalno mi javlja: no output file!? Driver koji sam dobio uz
> karticu je: rtl8150.c! Hvala svima!

Wrong language for this group. Sorry.

Bjørn
--
Bjørn Tore Sund "When in fear, and when in doubt;
(E-Mail Removed) Run in circles, scream and shout!"
Interaction! - Anonymous
http://www.interaction.worldcon.org.uk/

In article <(E-Mail Removed)>, Simon wrote:

>I would like to make local tests between two machines having a modem
>(simulating a RTC connection). Is it possible to connect directly the two
>modems each other and try to call a machine with the other one. If so what
>have I to do?

See if your modems have a "leased line" mode. See also the "Leased-Line"
mini-howto.

-rw-rw-r-- 1 gferg ldp 14216 Dec 15 2001 Leased-Line

Remember, the two modems will only connect at a maximum of 33.6k. The
Modem-HOWTO has additional details.

-rw-rw-r-- 1 gferg ldp 320925 Aug 10 08:45 Modem-HOWTO

Old guy

]In article <(E-Mail Removed)>, Simon wrote:

]>I would like to make local tests between two machines having a modem
]>(simulating a RTC connection). Is it possible to connect directly the two
]>modems each other and try to call a machine with the other one. If so what
]>have I to do?

In general no. Plug them into different local phone lines and have them
call each other.

(E-Mail Removed) (Bill Unruh) wrote:
>]In article <(E-Mail Removed)>, Simon wrote:
>
>]>I would like to make local tests between two machines having a modem
>]>(simulating a RTC connection). Is it possible to connect directly the two
>]>modems each other and try to call a machine with the other one. If so what
>]>have I to do?
>
>In general no. Plug them into different local phone lines and have them
>call each other.

Or just plug them into each other, and use ATA on one and ATO on the
other?

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) (E-Mail Removed)

(E-Mail Removed) (Floyd L. Davidson) wrote
> Or just plug them into each other, and use ATA on one and ATO on the
> other?

I think this would work, but you may have to provide a DC feed. In
the past I've used an old GP) 6000 series relay coil, and a 24V dc
supply. The relay coil forms an inductor in series with the junction
between two PSTN devices.

It gets much more difficult if you want to generate ringing.