Secutron MR-2900 Installation Manual page 26

Inner Door Ribbon Cables
Figure 25: Ribbon Cable Installation
Note: Inserting or removing the ribbon cables while the unit is powered can result in damage to the unit.
Standard Network Wiring
Figure 26: Standard Network Wiring
Note:
• Ensure that only one COM2 is connected to each COM1. If two or more are connected, the
network segment does not work.
• The following table shows the maximum wiring capacitance for the various baud rates supported
by the Network using the standard MR-2910. The maximum allowable line resistance is 680
ohms.
20
Two ribbon cables connect the Terminal Board to the Main
Circuit Board. These cables are on the hinged side of the
Inner Door and are long enough that the Inner Door can be
fully opened without removing the cables. Ensure that the
cables are not twisted and is seated properly in the
connectors. These cables must be attached before the unit
is powered (see Figure 25).
Standard Network wiring uses a twisted pair of wires
between each panel (see Figure 26). The COM1 of each
Unit is connected to the COM2 of the next Unit. MR-2944
Annunciator Unit are connected the same as the Control
Unit. Wiring is not polarity sensitive. Network wiring is
power-limited. Only COMLINK 1 is supervised for ground
faults.
COMLINK 2 is supervised for ground faults through its
connection to COMLINK1 of previous attached panel.