CSA 1300Z and 2300Z RS232 Control is not Null Modem
Table of Contents
CSA1300Z and CSA2300Z RS232 connection:
The CSA 1300Z and CSA 2300Z receive on their TX pin and transmit on their RX pin.
The CSA amplifiers are configured as a DCE (Data Communications Equipment) or modem, not a DTE (Data Terminal Equipment) or terminal/computer. They do not use a null-modem style of connection.
Use this wiring to control the CSA amps:
Control system TX or computer DB9 pin 3 TX -> TX CSA amp, RJ45 pin 6
Control system RX or computer DB9 pin 2 RX <- RX CSA amp, RJ45 pin 5
Control system Gnd or computer DB9 pin 5 Gnd - Gnd CSA amp, RJ45 pin 4 (or 8)
Per the RS232 spec, the pin that actually transmits data shall be at its negative voltage, -5VDC to -15VDC, when not transmitting. The pin that actually receives data shall be at 0VDC when not connected. This is true for both DTE and DCE devices, and can be easily confirmed with a DC voltmeter measured to Gnd.