Interlogix NVR 21 (S/P) User Manual - Manual (Page 14)

Chapter 2: Installation
8 TruVision NVR 21(S/P) User Manual
Figure 4: Expanding the system with an RS-485 signal distributor
1. Keypad
2. I/O box 3. RS-485 distributor
4. See section “RS-485 ports” on page 8
Caution : Most signal distributors are unidirectional. This means that the signal only
flows from the input towards the outputs. Consequently it is not possible to connect
several keypads.
See section “RS-485 ports” below to configure the RS-485 port communication settings.
RS-485 ports
There are two RS-485 ports on the rear panel of the recorder. See Figure 5 below for
the serial pin outs.
• Dome RS-485:
A and B: Connect pan, tilt, zoom control of PTZ dome cameras. A = +, B = -
C and D: Not used
G: Ground of dome camera
G: Ground of keypad
• Keyb: Connect the keypad.