Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rice!uw-beaver!milton!seymour
From: seymour@milton.acs.washington.edu (Richard Seymour)
Newsgroups: comp.sys.dec
Subject: Re: Decstation serial port <=> rs232(db25) connection
Keywords: Decstation serial port
Message-ID: <806@milton.acs.washington.edu>
Date: 4 Dec 89 21:45:07 GMT
References: <804@lclark.UUCP> <297@edison.UUCP>
Reply-To: seymour@milton.acs.washington.edu (Richard Seymour)
Organization: University of Washington, Seattle
Lines: 57


This is a guess about DEC's adapters, based on their descriptors.
I haven't done this yet, but i'm going to...
You can also do a little check-out with voltmeters.
 DTE="terminal or printer" (Data Terminal Equipment) pinout:
   on a 25-pin connector that means what-goes-on-the paper arrives
    on pin 3.  If there's a keyboard, it comes out pin 2 (as viewed
     from/at the terminal's connector).
 DCE= modem  pinout: 2/3 are reversed. (hence the output of the modem
    (pin 3) feeds the "input" of the printer (also pin 3)).

My guesses appear as lines without ">" far below...
 -- dick


In article <297@edison.UUCP> don@edison.UUCP (Don Kossman) writes:
>In article <804@lclark.UUCP>, dan@lclark.UUCP (Dan Revel) writes:
>> I would like to connect a modem or a terminal to the serial port on
>> a Decstation 3100.  How does the RJ-11 jack map to an RS-232 (DB-25)
>> pin configuration?
>
>i'm trying to do the same thing on a vaxstation 3100, which
>i assume has the same (strange) phone-like serial connectors.
>
>what i've found out so far is that the connector is NOT an rj-11, since
>the tab is offset from the centre.  DEC will sell you a cable with
>such a connector on either side (they call this an MMP connector).
>part number is BCE16E-xx where xx is 02, 10, 25 or 50.  this maps to
>2, 10, 25 or 50 feet.  cost is 4$ to 15$.  i believe you can get this
>via decdirect.
>
>then you need an MMP to RS232 adaptor.  this is where i'm stuck,
>since there are at least 6 and i don't know which is appropriate
>for what.  DEC tech support hasn't been able to help, they wanted
>to know which DEC modem or printer i wanted to connect... wouldn't 
>talk to me about HP laserjets and hayes modems.
>
>here is the info, such as it is, that i got from the DEC electronic store.
>
>        H8571-A 31$     25-pin passive adapter
   --- would probably be proper for a 25-pin modem (female??) 

>        H8571-B 26$     9-pin passive adapter
    --- would probably be proper for a 9-pin modem

>        H8571-C 21$     RS232 male adapter unfiltered
    --- would probably be modem pinout, like the -D, but without static filters

>        H8571-D 30$     25-pin adapter - male
     --- would probably be like the -C but with static filters in-line

>        H8571-E ???     male DTE 25-pin
     --- would connect to a terminal or printer (DTE=DataTerminalEquip)
           a modem is called DCE (Data Communication Equipment)

>        H8571-J $$$     9-pin serial printer
      ---- the 9-pin DTE pinout (instead of the -B modem pinout)