Two modems on one line????

A1ex radsky at
Tue Mar 8 16:48:25 UTC 2005

A1ex wrote:

> I have two modems installed, one integrated on the motherboard and an 
> external one on a serial port. At the present I am using the external 
> modem on both Windows XP and UBUNTU and the integrated modem output is 
> not connected because it seems to be a 100% Winmodem..  The external 
> modem is a little flaky in Windows XP---I sometimes have to kickstart 
> it by performing a modem query.but it works fine in UBUNTU..
> I would prefer having the integrated modem active for Windows XP and 
> the external serial one active for UBUNTU with both connected to a 
> single phone line to the jack box.wihout resorting to a switch to 
> select modems.
> Would there be a problem if I had both modems connected to the same 
> phone line?  My thinking is that there are already other appliances 
> connected to that same phone line and there's no problem and I think 
> all modems  have a tri-state output, that is high, low, and an 
> effectively disconnected state and the two  modems will never be 
> active at the same time.
> So, if one of the modems is in an effectively disconnected state when 
> the other one is is active, their outputs could safely be connected 
> together so only one line to the phone jack box is needed with just a 
> short jumper cable to connect the the two outputs
> together at the computer.
> What say you???  Did I miss something?
> alex , the world's oldest Linux fanatic.86+.
> ..
I hope you can follow this.....No success with either a parallel or 
series connection.  I tried the series connection both ways,  phone line 
to the external modem then  phone line to the internal  modem  with the 
other modem connected to telephone auxiliary outlet of the directly 
connected modem .   The end result is the external modem works  when it 
is selected  but when the internal modem is selected,, it reports a  
680  error---no dial  tone..The configurations are properly set so only 
one modem can be selected at a time..  

When the internal modem is the only connected modem, it works fine..


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