[GreenKeys] DTE & DCE on a modem

Brooke Clarke brooke at pacific.net
Thu May 22 10:55:21 EDT 2008


Hi Michael & Larry:

Those pin numbers only apply to a 25pin connector.  They are different for a 9 
pin connector.

Have Fun,

Brooke Clarke
http://www.prc68.com/P/Prod.html  Products I make and sell
http://www.prc68.com/Alpha.shtml  All my web pages listed based on html name
http://www.PRC68.com
http://www.precisionclock.com
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Web Cam

Michael O'Day wrote:
> Larry,
> If you want to use the modem without a full RS-232
> handshake, you may have to "hot wire" the modem by
> connecting some of the signals together. We used to do
> it by cutting the wires inside the cable's connector
> shell, leaving a half-inch of wire on each pin to be
> connected, and soldering them together inside the
> connector shell. The basic RS-232 handshake is:
> 
> PIN #    Signal   Signal
>  2         Tx     Data Transmit - to modem
>  3         Rx     Data Receive -  to terminal
>  4         RTS    Request to send - to modem
>  5         CTS    Clear to send - to terminal
>  6         DSR    Data set ready - to modem
>  8         DCD    Data Carrier Detect - to terminal
>  20        DTR    Data terminal ready - to modem
>  7         GRD    Signal Ground - common to all
> 
> The hot wire sequence is tie pins 4&5 together, and
> separately tie pins 6,8&20 together. There is also a
> ring indicator signal on pin 22 (for auto-answer
> modems), tell the modem to ignore RI if it has that
> option.
> 
> Mike O'Day  N9ODM
> 
> --- Larry Tighe <larryradio at worldnet.att.net> wrote:
> 
>> Howdy Folks,
>>
>> Got my hands on some Black Box CL050A modems. 
>> Planning to try keying a HV 
>> transistor with the RS-232 outputs.  They are
>> designed to key a current loop 
>> which they supply 18 volts to.
>>
>> Can anyone tell me what DCE and DTE means?  There
>> are dip switches that'll 
>> have to be set up....
>>
>> Thanks,
>> Larry
>> www.antiquetelephone.com 
>>
>> _______________________________________________
>> GreenKeys mailing list
>> GreenKeys at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/greenkeys
>>
> 
> 
> 
>       
> _______________________________________________
> GreenKeys mailing list
> GreenKeys at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/greenkeys
> 


More information about the GreenKeys mailing list