AMG Systems Ltd. reserves the right to make changes to this document without
notice. The information herein is believed to be accurate. No responsibility is
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Page 5 of 7
AMG2684 Instruction
Sheet D15700-00
Red
-
Fibre Loop Present, no TX selected on this
channel
Off
– no video present on video CH7 input BNC
Video Present CH8 .............................. Green
– video signal present on video CH8 input BNC
Red/Green -
Channel present , no video
Red
-
Fibre Loop Present, no TX selected on this
channel
Off
– no video present on video CH8 input BNC
Data Present TX .................................. Green
– logic one present on the data input
Red
– logic zero present on the data input
Off
– tri-state off or no connection on the data input
This represents the data signals being transmitted on the optical f ibre
Data Present RX .................................. Green
– logic one present on the corresponding data
output
Red
– logic zero present on the data output
Off
– tri-state off on the data output
This represents the data signals being received on the optical fibre
Physical Information
Dimensions
Height .................................................. 109mm
Width.................................................... 218mm
Depth ................................................... 70mm
Weight.................................................. 800grams
Mounting Details
The unit is designed to mount into a panel via the two mounting slots of 4.5mm x 10mm.
Configuration of the RS422/485 Data Channel
The RS422/485 data channel can operate in two modes that are set by SW2 on the main PCB. (See
below for
removal of the PCB
and access to SW2)
Mode 1 –
RS485 two wire half duplex transmission.
Mode 2 –
RS422 four wire full duplex transmission. In this mode the RS422 output will transmit a
tristate condition as well as logic high and logic low for systems which require bus-ing of
the RS422 four-wire connection.
MODE
Configuration Details
SW2
position 1
SW2
position 2
SW2
position 3
SW2
position 4
1
RS-422 4 wire Point-to-Point -
and RS-422 BUS system
OFF
OFF
OFF
OFF
2
RS-485 2 wire BUS systems
OFF
ON
ON
ON
The data input for both the RS485 and the RS422 modes detects a tri-state input condition by
monitoring the differential voltage level across the input. A differential level below 500mV positive or
negative will be detected as a tristate condition. A level above 500mV positive or negative will be
detected as a logic 1 or logic zero respectively.
It is important therefore to terminate the RS485
bus or the RS422 input bus using 120ohms if a pre-bias is present on the RS485 or RS422 bus.
A large number of third party equipment manufacturers apply a pre-bias on their RS485 bus. This pre-
bias is applied by pulling one arm of the RS485 bus high (+5 volts) and the other arm low (0 volts)
using high value resistors within the third party equipment. In order to ensure that a tri-state condition
is detected by the AMG2700 equipment, then these resistors should have a value above 1kohm.