Date   : Thu, 26 Nov 1987 12:05:00 EST
From   : John C Klensin <Klensin@MIT-Multics.ARPA>
Subject: Serial cables for the Geneva

Steve,
  Before you do anything drastic, suggest you try calling your local
Epson distributor (call Epson's widely-advertised number in Torrance if
you don't know where the distributor is).  They claim to have Geneva
parts; sometimes they do.  The dealers are, of course, useless.  Failing
that, try DAK and see if you can convince them to sell you the cables
without a computer attached.
   If that fails, two comments:
 1) If you can find the "round-type miniature" connector (Epson
variously refers to it that way and as a mini-DIN), then
    Round connector             DB25
    1 GND                   7
    2 TXD                   2
    3 RXD                   3
    4 RTC                   4 RTS
    5 CTS                   5
    6 DSR                   6
    7 DTR                  20
    8 CD                    8
    E CG                    1
 I think "E" is the shell, and can't account for the "RTC" label - it
may be a typo.  This information is copied out of the Technical Manual
for the PX-8.
 2) Your big problem if you decide to write one yourself will be getting
the little mini-pseudo-DIN round connectors.  The last time I looked
(about six months ago, I admit), couldn't find a source of supply.
However, Apple uses the same connector on their newer Macs, and sells an
expensive little converter from that connector to a DB9 (!)  female.  I
got one of those some months ago with the intent of building a backup
for my Epson cables (I've got one broken one, and am not impressed with
their quality or robustness), but have not been able to get around to
ringing it out and building the appropriate DB9->DB25 converter to
string together with it.  I have no particular reason to believe that
Apple's pinouts have anything to do with Epson's.  If anyone has figured
this one out, and has worked out the pin configuration of the DB9->DB25
converter that converts Apple's round-connector->DB9 converter into a
Geneva round-connector->DB25 serial, I'd be interested.