[sci.electronics] Bell Modem Problem

eap@bucsb.bu.edu.UUCP (Eric Pearce) (08/07/87)

    I have a wierd problem with a Bell Dataphone modem (212A 1200/300 baud)
It works fine for short periods of time, but if it is used more than an hour
or so, it hangs up the connection.   My first thought was that it was over-
heating, but it is an external modem and the case doesn't get very warm.  
The little wall transformer does get warm though - even more so if it is
left plugged in for a while.  It works fine otherwise.   It hangs up with
a loud 'click' from the relay inside the case.  Maybe there is thermal switch
somewhere in the wall transformer or modem itself ?   Neither the transformer
or the modem is enclosed or blocked in any manner that would prevent normal
heat dissipation.  Please do not flame me for owning such a device, I know
it doesn't have auto-dial or any other features, but what do you expect for
$80 at computer show ?   *Any* suggestions welcome... 

/*
 It's not that bad, you just have to wire a momentary switch to the phone 
 connector that puts it in 'data' mode when you get a carrier.  I have a
 regular K-500 sitting on top of it for the dialing part.                
*/   



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