Richard S. Shuford wrote:

> dan <cephalopod(at)mac.com> wrote:
> |
> | I picked up an HP 2645A terminal the other day, and I think it's pretty
> | neat, but I can't figure out how to make a serial connector for it!  (It
> | has card-edge connectors in the back, not DB25 or anything recognizable.)
>
> There is some connector-pinout information available from the link
> to "Hewlett-Packard video-terminal products" on the "Various" page of
>
>     http://www.cs.utk.edu/~shuford/terminal_index.html
>
>  ...Richard S. Shuford
>     shuford(at)list.stratagy.com
>
>

Yes, here it is (from the above site)....

.S.R. Modem Cable (30-pin 2F to 25-pin 3M)

Computer/Modem (DCE)                    Terminal (DTE)
====================                    ==============

Signal          Pin     Dir.    Pin     Signal
===================     ====    ============================
Send Data       2       <--     2       Send Data
Receive Data    3       --> 3       Receive Data
RTS             4       <--     4       RTS
CTS             5       --> 5       CTS
DSR             6       --> 6       DSR
Common Return   7       <-> 7       Common Return
CD              8       --> 8       Carrier Detect
Secondary CD    12      --> 12      Secondary Carrier Detect
Secondary RTS   19      <--     19      Secondary RTS
DTR             20      <--     20      DTR
Freq. Select    23      --> 23      Frequency Select

Male Connector (DB25)           Female Connector (30 pin card edge)

 =========================================================================

Where:

         RTS     Request To Send
         CTS     Clear To Send
         DSR     Data Set Ready
         DTR     Data Terminal Ready
         CD      Carrier Detect


//////////////////////////////////////////////////////////////////////////////

   [Archiver's note:  I do not have real knowledge, but some
    HP terminals are rumored to use ENQ/ACK software handshaking
    instead of the more common XON/XOFF handshaking.]

------------------------------------------------

Since you have a couple of connectors on the back, the correct one is on
the card labeled 'datacom' or 'enh datacom'. The easiest way to tell
which one is to open the terminal and look. All cards are labeled  on
the top.

To open the terminal... It is hinged at the back and there are two
latches near the front. Along each side of the terminal is the joint
between the top and bottom. About 1.5 inches from the front of the joint
is a small gap. The latches are through the gap. Straighten a paper clip
and insert to unlatch the top. You should only need to insert the clip
about  1/2 inch, no more. (Doing this with the power off is advised.)

Unlatch both sides and the terminal can be opened. There is a catch at
the back to hold it open.

These terminals generally were used with enq-ack handshake. You may want
to check the setup to verify the handshake.

Enjoy,

Craig

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