Communication to a controller, Mr-50 controller to additional sio units, Mr-50 – Keri Systems MR50 User Manual
Page 3
Mercury Security Corporation © 2014
MR50
DOC 10107-0009
REV 2.03
Page 3
3. Communication to a Controller:
The MR50 communicates to a Mercury Security intelligent controller (EP2500 for example) via a half
duplex multi-drop 2-wire RS-485 interface. The total cable length is limited to 4,000 feet (1,219
meters). Shielded cable of 24 AWG with characteristic impedance of 120 ohm is specified for the 2-
wire RS-485 interface. The last device on each end of the communication line should have the
terminator installed (set jumper J4 on).
Address, Baud Rate and Encryption Configuration Jumpers:
Each Interface (MR50, MR52, etc.) must be configured to have a unique address and correct baud
rate. The address and baud rate are selected by installing the specified jumpers.
Note 1: Firmware revisions prior to 1.39.1, the 115200 baud rate setting is 2400 baud.
Note 2: Firmware revisions prior to 1.39.1, jumper 8 is not defined, remove jumper.
MR-50
CONTROLLER
TO ADDITIONAL
SIO UNITS
J3
7
TR+
TB1
3
J2
2
1
6
5
4
GND
TR-
DAT
VO
D0
J4
8
J3
7
TB1
3
2
J2
1
6
5
4
TR+
GND
TR-
8
J4
DAT
VO
D0
TR-
GND
TR+
MR-50
LAST UNIT ON
COMMUNICATION
LINE - TERMINATOR
INSTALLED