Mercury Security © 2016
MS-I8S
DOC 10107-0055
REV 1.01
Page 2
3. Communication Wiring:
The MS-I8S communicates to the MS-ICS intelligent controller via a 2-wire RS-485 interface. The
interface allows multi-drop communication on a single bus of up to 4,000 feet (1,200 m). Shielded cable
of 24 AWG with characteristic impedance of 120 ohm is specified for the RS-485 interface.
The last devices on each end of the cable should have the terminator installed (install jumper J1).
4. Alarm Inputs Wiring:
Input circuits can be configured as unsupervised or supervised. When unsupervised, reporting consists
of only the open or closed states.
When an input circuit is configured for supervision, then the MS-I8S board also monitors the following
abnormal circuit conditions: open circuit, shorted circuit, the grounding of either side of the circuit*, or the
introduction of a foreign voltage*. A supervised input circuit requires adding two resistors to the circuit to
facilitate proper reporting. The standard supervised circuit requires 1k Ohm, 1 % resistors and should be
located as close to the sensor as possible. Custom end of line (EOL) resistances may be configured via
the host software.
* Grounded and foreign voltage states are not UL 294 required and therefore not verified by UL.
The input circuit wiring configurations shown are supported, but may not be typical:
5. Cabinet Tamper Switch Input Wiring:
Connect TB10 terminals to the cabinet tamper switch. The cabinet tamper switch must
be a normally closed contact. Do not use EOL resistor(s). Install a jumper wire to these
terminals if a cabinet tamper switch is not used.
+12VDC
TR+
TR-
GND
1K,1%
1K,1%
1K,1%
1K,1%
Standard Supervised Circuit,
Normally Open Contact
Normally Closed Contact
Standard Supervised Circuit,
Normally Closed Contact
Unsupervised Circuit,
Normally Open Contact
Unsupervised Circuit,
TO INPUT
TERMINAL
BLOCK
TAMPER
GND
