🚀 go-pugleaf

In article <38684@sdcc12.ucsd.edu>, sakelley@euclid.ucsd.edu (Scott Kelley) writes:
>
> However, the other deck I want to go to is a Sony D-2 digital video
> deck. It apparently has a 15-pin D-connector that provides an RS-422
> interface to the deck. And it's this deck that's got me stumped. Can
> anyone tell me how to make a cable for it? The main difficulty I'm
> having is that I'm used to RS-232, and both the mac and this deck
> actually want to talk RS-422. And I don't know how to work with RS-422.

I've successfully ignored this fact when working with Macs for several years
now :-). RS-422/423 is backward-compatible with RS-232C.

> What gets connected to what? Can anybody help me build a cable for this?
> Here's what I know about the pinouts of the two devices:
>
> Sony Deck (DB-15):    Apple Serial Port (DIN-8):
> ------------------    --------------------------
> 2  Rx-                  1  HSKo
> 3  Tx-                  2  HSKi
> 8  Spare                3  TxD-
> 9  Gnd                  4  Gnd
> 10 Rx+                  5  RxD-
> 11 Tx+                  6  TxD+
> 12 +12v                 7  NC
> 13 Frame Gnd            8  RxD+
> 14 Gnd
> All others NC
>
> For RS-422, Do I connect Tx+ to Tx+, Rx+, or Rx-, or what? I've got no
> idea. And I don't want to damage their mind-bogglingly expensive video
> equipment!!!

At a guess I'd say you need a "null-modem" connection. That is, connect
Tx+ on one side to Rx+ on the other, and similarly for Tx- and Rx-. Also
connect the grounds together. I see there're no handshake pins on the Sony side,
so I guess you should leave the HSKo and HSKi pins unconnected on the Mac side.

The Mac serial drivers can be configured to run in various modes, including
both hardware handshake (using those HSK lines) and software (XON/XOFF)
handshake. I assume the Sony would use either software handshaking, or no
handshaking at all. A less likely alternative is that it uses some other
strange pair of characters (e g ETX/ACK) for its handshaking; if need be,
the Mac serial drivers can be reconfigured to use these.

Just a thought: what software are you running on the Mac to drive the
serial port? That might have limits on the amount of reconfiguring it will
allow you to do.

I should admit I'm no hardware type. If I get into trouble, I usually end
up calling on my technician colleagues for help. But I *have* successfully
worked out a few odd RS-232C connections in my time.

Lawrence D'Oliveiro                       fone: +64-7-856-2889
Computer Services Dept                     fax: +64-7-838-4066
University of Waikato            electric mail: ldo@waikato.ac.nz
Hamilton, New Zealand    37^ 47' 26" S, 175^ 19' 7" E, GMT+12:00