Kramer Electronics RC-76M - Manual (Page 13)

10 RC-76M/ RC-712M - Installing the RC-76M/RC-712M
3. Connect the RELAY terminal block connectors as follows:
 Connect RELAY C and 1 to the screen
 Connect RELAY C and 2 to the lighting system
4. Connect the GPI/O 1 port to a motion detector.
5. Connect the Ethernet port to a network.
Figure 4: Connecting the RC-712M
4.2.1.1 Connecting RS-232 Devices
You can control up to two AV devices such as a projector or an RS-232 display by
connecting them to the RC-76M/RC-712M via their RS-232 connection.
To connect a device to the RC-76M/RC-712M via RS-232:

Using a straight cable, connect pin 2 to TX, pin 3 to RX and pin 5 to GND on
the RS-232 terminal block connector of the RC-76M