Epson GT-6500 EN - Manual (Page 165)

Signal pin assignments
In this table, the direction of the signals is given relative to the
scanner.
Pin No. Signal I/O Description
1 C.GND - Chassis ground
2 TXD Out Transmit data
3 RXD In Receive data
4 RTS Out Request to send
5 CTS In Clear to send
6 DSR In Data set ready
7 S.GND - Signal ground
8
−
19 NC - -
20 DTR Out Data terminal ready
21
−
25 NC - -
Cable wiring
A typical example of cable wiring is shown below.
Interface Specifications A-3