Mercury Security © 2015
EP4502
DOC 10107-0039
REV 1.02
Page 4
6. Communication Wiring:
The EP4502 controller communicates to the host via the on-board 10-BaseT/100Base-TX Ethernet
interface (port 0).
The serial I/O device communication ports, TB2 for port 1 and TB3 for port 2, are 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. 1-twisted pair with drain wire and shield, 120 ohm
impedance, 24 AWG, 4,000 ft. (1,219 m) maximum 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 Wiegand, magnetic stripe, and 2-wire RS-485 electrical interfaces. Power
to the reader is selectable: 12 Vdc (VIN must be greater than 20 Vdc), or power is passed-through
(PASS) from the input voltage of the EP4502 (TB1-VIN) and is current limited to 180 mA for each
reader port. Readers that require different voltage or have high current requirements should be
powered separately. Refer to the reader manufacture specifications for cabling requirements. In the
2-wire LED mode the Buzzer output in used to drive the second LED. Reader port configuration is
set via the host software.
Data1/Data0 - Clock/Data
Reader
2-wire RS-485
Device
TR-
TR+
GND
TB3
TR-
TR+
GND
TB2
Port 1 To Serial I/O Devices
Port 2 To Serial I/O Devices
GND
DAT/D0
CLK/D1
BZR
LED
VO
TB8 OR TB9
POWER
TR+ (B)
TR- (A)
GND
GND
DAT/D0
CLK/D1
VO
TB8 OR TB9
GND
DAT/D0
CLK/D1
BUZZER
LED
POWER
