Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!ucsd!ucbvax!tut.cis.ohio-state.edu!att!cbnews!feb
From: feb@cbnews.ATT.COM (Franco E. Barber)
Newsgroups: comp.sys.att
Subject: Re: combo board problems
Message-ID: <6759@cbnews.ATT.COM>
Date: 21 May 89 16:43:33 GMT
References: <12185@rcsuna.UUCP>
Reply-To: feb@cbnews.ATT.COM (Franco E. Barber)
Distribution: usa
Organization: AT&T Bell Laboratories
Lines: 56

In article <12185@rcsuna.UUCP> rhaar@rcsuna.UUCP (Bob Haar CS50) writes:
>I am having a problem with a combo board and need to
>get some help.


>3) is the loop-back connecto that I made correct? It works for
>   testing the standard serial port. The connections I made are:

>	|-- pin 2 (Data transmit)
>	|
>	|-- pin 3 (Data receive)

>	|-- pin 4 (Request to send)
>	|
>	|-- pin 5 (Clear to send)
>	|
>	|-- pin 8 (carrier detect)


>	|-- pin 6  (Data set ready)
>	|
>	|-- pin 20 (Data terminal ready)
>	|
>	|-- pin 22 (Ring detect)

>Bob Haar
>G.M. Research Labs

>uunet!edsews!rphroy!rcsuna!rhaar
>HAAR@GMR.COM (CSNET)

That connector works only for the built-in serial port.
The loopback connector for the expansion ports has to cross
connect the two ports on the card. Ie, pin 2 on port 1 to pin 3 on
port 2, etc.  The diagnostics even test the external clock inputs.

here are the appropriate connections:

   port 1                         port 2
TxD 2                   ----- 3  RxD
RxD 3                   ----- 2  TxD

RTS 4                   ----- 5  CTS and 8  CD
CTS 5 and CD  8         ----- 4  RTS

DSR 6 and RI 22         ----- 20 DTR
DTR 20                  ----- 6  DSR and 22  RI

TxClk 15 and RxClk 17   ----- 24 DTE TxClk
DTE TxClk 24            ----- 15 TxClk and 17 RxClk

GND 7                   ----- 7  GND


Franco Barber
att!cblpe!feb