The 6-pin modular jack SA bus connection (Figure 1) is a
straight-through (not a crossover) connection and that uses a 6-wire connector cable
(with 6-pin RJ-style modular jacks) to connect SA devices to network sensors
Sensor. On the 6-wire cable, two wires are used for network communication, two wires
for network sensor power, and two wires supply 15 VDC (200 mA maximum) power to the
devices connected to the sensor.
The cable connected to the SA bus 6-pin modular jack is a straight-through cable and cannot exceed 30 m (100 ft). Do not use crossover cables on the SA bus.
The SA bus 6-pin modular jack supports only one device and no other SA device may be daisy-chained to the port.
Important: Failure to adhere to these wiring details may cause your network sensor to
function incorrectly. You are not able to connect to the system using the
Converter, the Handheld Variable-Air-Volume (VAV) Balancing Sensor, nor can you
expand the system with future offerings.
Note: Do not mix RJ-style modular (phone) jack and screw terminal devices on the SA bus. Due to the
permanent internal SA bus EOL termination contained in
CH-PCAs, CH-PCGs, CH-PCVs, and CH-PCXs
, using both the phone jack and terminal block
effectively puts the EOL termination in the middle of the SA trunk, creating a star
network configuration. This configuration violates the RS-485 network wiring
guidelines and can cause unpredictable communication problems.
Figure 1. 6-Pin Modular Jack Pinout Details