RS-232-C Null Modem Cables

The following diagram illustrates a synchronous null modem that allows you to connect two Sun machines that each supply clocking, using the RS-232-C interface. Each Sun machine supplies clocking on pin 24. The null modem routes this clocking to pin 17 on the opposite side to provide receive clocking.

In x25tool Link Editor window, set the Tx Clock parameter to the bit rate you want (not External) on both machines.

Figure A-1 RS-232-C Null Modem: Both Sun Machines Supply Clocking

The following diagram illustrates a synchronous null modem that allows you to connect a Sun machine to another Sun or non-Sun machine, using the RS-232-C interface. The Sun machine supplies both the transmit and receive clocks for the other machine. Note that this null modem is not symmetrical.

In x25tool Link Editor, set the Tx Clock parameter to the bit rate you want (not External) on the Sun machine that is to supply clocking.

Figure A-2 RS-232-C Null Modem: Sun Machine Supplies Clocking for Both Sides