3B15 Modem Problem

[Frank G Kienast]

At work, I am trying to connect a Hayes-compatible modem to an AT&T 3B15 
computer.  I have found that, in order to make outgoing calls using cu, it 
is necessary to wire the cable so that DCD (carrier detect, pin 8) is always 
high (otherwise I get the message "Can't access device" whenever I try to 
call out).  But having DCD high all the time creates problems when I am 
ready to disconnect after a call.  After the other end hangs up, I get the 
"NO CARRIER" message from the modem, but my terminal is still connected.  
The only two ways I have found to break the connection so another terminal 
can call out or someone can call in are: 1) Turn off the modem.  This 
results is an immediate "Lost Carrier" messages and returns me to the Unix 
prompt.  When the modem is turned back on, it is ready for the next call.
2) Enter "~.." (tilde dot dot).  This returns me to the prompt, but it is 
necessary to log in as root and kill the uugetty on the modem line to free 
it for further incoming or outgoing calls.
 
Is there any way to wire my modem differently or somehow set some parameter 
differently so my modem will disconnect properly?  Please E-mail your 
responses.  I will post a summary along with the results.
 
 
In real life: Frank Kienast
Well: well!fgk at ucbvax.Berkeley.EDU
CIS: 73327,3073
V-mail: 804-980-3733