Mercury Security © 2015
EP1502
DOC 10107-0031
REV 1.06
Page 4
6. Communication Wiring:
The EP1502 controller communicates to the host via the on-board 10-BaseT/100Base-TX Ethernet
interface (port 0) and/or RS-232 interface (port 1). RS-232 interface is for direct one to one connection to
a host computer port or via modem, 25 feet maximum.
The serial I/O device communication port (TB3) is a 2-wire RS-485 interface which can be used to connect
additional I/O panels. The interface allows multi-drop communication on a single bus of up to 4,000 feet
(1,219 m). Use twisted pairs (minimum 24 AWG) with drain wire and shield for communication.
IMPORTANT NOTE!
Install the termination jumper ONLY on the panel at each end of the RS-485
bus. Failure to do so will compromise the proper operation of the communication channel!
7. Reader Wiring:
Each reader port supports a reader with TTL (D1/D0, Clock/Data), F/2F, or 2-wire RS-485 signaling. Power
to the readers is selectable: 12 Vdc (VIN must be greater than 20 Vdc), or power is passed-through (PASS)
from the input voltage of the EP1502 (TB1-VIN), 180 mA maximum per reader port. Readers that require
different voltage or have high current requirements must be powered separately. Refer to the reader
manufacture specifications for cabling requirements. In the 2-wire LED mode the buzzer output is used to
drive the second LED. Reader port configuration is set via the host software.
To fully utilize each reader port:
TTL signaling requires a 6-conductor cable (18 AWG)
F/2F signaling requires a 4-conductor cable
RS-485 signaling requires two 2-conductor cables. Use one cable for power (18 AWG) and one
cable for communication (24 AWG, with drain wire and shield)
J7
– Reader Power Select
If the input voltage to the EP1502 is 12 Vdc, jumper J7
MUST
be in the PASS position.
RXD
TXD
RTS
CTS
GND
Port 1, RS-232 To Host
TR-
TR+
GND
To serial I/O Devices
TB2
TB3
1
1
