Available on the Commodore C64/C128. Software emulated. The
signals does not have true RS232 levels. It's TTL level, and
RXD/TXD is inverted. It's just the normal User Port, used as a
RS232 port.
(at the computer)
UNKNOWN CONNECTOR at the computer.
Pin
Name
RS232
Description
A
GND
GND
Protective Ground
B+C
FLAG2+PB0
RxD
Receive Data (Must be applied to both pins!)
D
PB1
RTS
Ready To Send
E
PB2
DTR
Data Terminal Ready
F
PB3
RI
Ring Indicator
H
PB4
DCD
Data Carrier Detect
K
PB6
CTS
Clear To Send
L
PB7
DSR
Data Set Ready
M
PA2
TxD
Transmit Data
N
GND
GND
Signal Ground
Contributor:
Joakim Цgren,
Arwin Vosselman,
Mark Sokos
Source:
Usenet posting in comp.sys.cbm - Help on modem -> c64 by Lasher Glenn
(at the computer)