Solution:

There are 4 terminal resistors space on old PCL-745: R12 - port 1 CTS+/- R16 - port 1 RX+/- R26 - port 2 CTS+/- R28 - port 2 RX+/- There are also 4 terminal resistors space on PCL-745B: TR1 - port 1 TX+/- TR2 - port 1 RX+/- TR3 - port 2 TX+/- TR4 - port 2 RX+/- If the customer doesn't use RTS/CTS connection, he can use TR2 and TR4 for RX termination resistor. If he must use CTS termination, he needs to solder the resistor on PCB or DB-9 connector directly