GW INSTEK GTL-232A
The GTL-232A is an RS-232C communication cable for GW INSTEK's PSP-603, PSP-405, and PSP-2010 series. It is used when the equipment needs to be controlled or connected via RS-232 remote control, and it is therefore an integral part of the setup when working with remote control in test and measurement environments.
The cable is a 9-pin female-to-female null modem cable with a length of approximately 2000 mm. The null modem configuration means it is designed for direct communication between equipment, where signals are crossed so that the correct transmit and receive lines are in place. In the PSP series manual, the GTL-232A is specified as the special cable to be used for RS-232 remote control.
The internal connection is documented by the manufacturer: pin 2 is RxD, pin 3 is TxD, pin 4 is +12V (DTR), pin 5 is GND, while pins 1, 6, 7, 8, and 9 are not connected. This is useful when wanting to understand how the cable is constructed in relation to the specific control of the instrument.