Macintosh Plus: Circular 8 to DB-9 Adapter Pinouts
Circular 8 Signal DB-9
1 HSKo (+12V) 6
2 HSKi 7
3 TXD- 5
4 GND 3*
5 RXD- 9
6 TXD+ 4
7 No Wire
8 RXD+ 8
GND 1*
* Pins 1 and 3 on the DB-9 end are jumpered together.
The pins on the male end of the circular 8 connector are numbered as shown:
6 7 8
3 4 5
1 2
The pin assignments for the DB-9 connector on the AppleTalk connection module
are as follows:
Signal Name Pins
DB-9
RXD+ 8
TXD+ 4
RXD- 9
TXD- 5
Case ground DO NOT DIRECT CONNECT CASE GROUND TO CABLE SHEILD.
The case ground signal goes from the connector module shell through a ground
isolation network in the connector module to the shield of the cable. The
ground isolation network isolates grounds and helps prevent ground currents.
No further case grounding should be made.