Re: Appletalk/Phonenet box wiring (Re: ...phoneNet connection to Win2K?)

[david@uow.edu.au (David Wilson)]

mister_boffo@hotmail.com (Mister Boffo) writes:
>And would ya know it, I've got a disassembled Appletalk dongle
>right here. Wiring looks like this inside:

>                          T1
>BUS Wire 1 --+------+---      ----------+--------- Serial Red
>             |      |   ) ## (          |
>          Term R2   |   ) ## (          `--- R4 -- Serial Blu
>             |      |   ) ## (
>          Term Sw   |   ) ## (    
>             |      |   ) ## (
>BUS Wire 2---+----- | --  ##  --- N/C
>                    |   ) ## (
>                    |   ) ## (
>                   R1   ) ## (
>                    |   ) ## (          .--- R3 -- Serial Wht
>                    |   ) ## (          |
>BUS Ground----------+---      ----------+--------- Serial Grn
>                    |
>                    |
>                    `-----------+-- R5 --+-------- Serial GND
>                                |        |
>                                `-- C1 --'
>                              (noise filter)

>Okay, I don't know what the serial wire colors represent but
>it seems fairly easy to figure out. The main thing you need to
>know about RS422 is that you might say the sending line has
>its own ground, and so does the receiving line. It's usually
>represented as RX+ RX- and TX+ TX-

And here are the serial connections from page A-4 of "Inside Appletalk"
Second Edition:

Wire	Sig	MiniDIN-8	DE-9
-------------------------------------
Red	TxD-	pin 3		pin 5
Blu	RxD-	pin 5		pin 9

Wht	RxD+	pin 8		pin 8
Grn	TxD+	pin 6		pin 4

GND	Case	Shield		Shield

>In order for you to send a signal you have to send from RX+
>through the transformer and out to RX-. Similarly to receive
>a signal the transformer must connect to TX+ and TX-.

The +/- signals are differential. When TxD+ is +3volts the TxD-
will be -3volts giving 6 volts between them. When the signal changes
from logical 1 to logical zero the polarities of both lines change.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia