P8 - Serial Port 2 - David Griffith P112 Assembly And Operation Manual

Pin 1 is at the top-left when holding the board with the battery to the bottom-
right. The pin assignment is such that a 26-way ribbon cable (with line 26
removed) may run direct to a DB-25 connector, presenting a standard IBM
parallel printer interface.
The interface offers basic bidirectional capability; expanded (ECP/EPP) fea-
tures are not available.
9.8 P8 — Serial Port 2
Pin Assigment
1 DCD (in)
2 RXD (in)
3 TXD (out)
4 DTR (out)
5 Ground
6 DSR (in)
7 RTS (out)
8 CTS (in)
9 RI (in)
10 Not used
Pin 1 is at the top-left when holding the board with the battery to the bottom-
right.
See P4 for details. This port is implemented on the combination IO chip, and
is strictly PC compatible.
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