51-52-33-157 Rev. 6
Page 11 of 14
Use shielded CAT5 cable (Honeywell part no. 514514032). Cable length must be less than 100 meters. For
longer distances use Ethernet switches between cables. The use of Ethernet cables in excess of 100 meters
may cause transmission delays that could have adverse affects on performance.
RS485
For RS485 between Control Station and HC900, construct a cable as follows.
1.
Cut off one connector of the shielded CAT5 cable.
2.
Connect the wires indicated to the 3-plug connector that was supplied with the HC900 CPU module.
See table below.
Shielded CAT5 cable
3-plug connector
Signal Pin
Terminal
Shield (aluminum-
polyester foil tape with 26
AWG stranded drain wire)
Connect
to
1
TXA 2
Connect
to 2
TXB 1
Connect
to 3
RXA 3
RXB 4
TXEN 5
Common 6
TXB 7
Connect
to 3
TXA 8
Connect
to 2
3.
Cut off any unused wires in the cable and insulate with heat shrink tubing or other appropriate
insulating material.
This connector plugs into the HC900’s RS485 port; the RJ45 connector plugs into the Control Station’s
RS485 port.
3
2
1
