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Model ATC-107
RS-232 to RS-422/485 Isolated Interface Converter
User's Manual
1.0 General Description
The ATC-107 is a series of a bi-directional interface
converters, Models ATC-107 optically isolate and convert
unbalanced, full or half-duplex RS-232 signals to 0ptically
isolated, balanced, full or half duplex RS-422 or RS-485
signals at baud rates up to 115.2 kbps. These units also
surge suppress the RS-422/485 lines. They feature Send
Data Control circuitry so no software control of handshake
lines is required in RS-485 mode. ATC -107 has built-in
isolators for high voltage (2500V) protection. it provides
Point-to-Point, Multi drop and Simplex Operations. The
ATC-107 can be powered from the DC 9V, 200mA power
adapter, One slide switches are used to configure its
operation mode.
2.0 Specifications
2.1 Interface
Conforms to EIA /RS-232 and RS-422/485 standards.
2.2 Connectors and signals
The ATC-107 has a DB-25 female connector on the RS-232
side and a terminal block connector on the RS-422/485 side
RS-232 Side:
Connector: DB-25 Female.
Signals：ATC-107 will be connected into a DTE interface.
Use Pins 3 (TXD)、2 (RXD) and 7 (Near side ground) .
Use Pin 2、4、 20 to power from ATC-107 RS-232 side.
RS-422/485 Side:
RS-422 Connector: 4 position terminal block : (1)T+，
(2)T-、 (3)R-、(4)R+.
RS-485 Connector: 4 position terminal block: (1)485+，
(2)485-.
Signals: Dual-duplex or Half-duplex two-wire/four-wire
operation only.
2.3 Data Rate :
300 to 115.2 KBPS, up to 1.2km at 38.4 KBPS.
2.4 Sending Control
The ATC-107 can use handshake lines to power the
converter, no handshaking is required to control the
RS-422/RS-485 driver. the RS-485 driver is automatically
enabled during each spacing state on the RS-232 side.
During the marking or idle state, the RS-485 driver is
disabled and the data lines are held in the marking state by
the 4.7K Ohm pull-up and pull-down resistors.
2.5 Operating Distance
Data Rate (KBPS)： 38.4 19.2 9.6 4.8
Maximum Distance (km)： 1.2 2.0 2.5 3.5
(using 24 AWG wire)
2.6 Power
At the RS-422/485 side，ATC-107 is powered by an external
power supply (+9VDC to +12VDC@200mA) by a AC/DC
adapter. At the RS-232 side It powered by RS-232 signals
TXD,RTS or DTR ,We only need one of these signals, the
ground signals in two sides are different.
2.7 Switches:
RS-422/RS-485 switch selectable for RS-422/485 operation
mode. If you set ATC-107 to RS-422 mode，ATC-107 can
convert the TD and RD signals of RS-232 into balanced
Dual –duplex RS-422 signals. If you set ATC-107 to RS-485
mode，ATC-107 can convert the TD and RD signals of
RS-232 into balanced Half –duplex RS-485 signals.
2.8 LED light
One LED indicates sending data to (RED) or receiving data
from (GREEN) RS-422/485 bus.
2.9 Isolation :
Optical Isolation is rated at 2500V.
2.10 Dimensions :
79mm × 54mm × 20mm
2.11 Environment :
0* to 50* C，5% to 95% relative humidity.
3.0 Installation
3.1 RS-232 and RS-485 Interface
In the RS-232 side:
The RS-232 interface is a DB-25 female connector， It can
be plug into a DTE interface.
In the RS-422/485 side:
Screw Terminals-The ATC-107 is supplied with 4 screw
terminals marked 1(T+)/(485+)、2(T-)/(485-)、3(R-)、4(R+)，.
3.2 Connection Diagram
3.21 ATC-107 connecting RS-422 Device/(Four wire
RS-485)
RS-422/(Four wire RS-485)mode
ATC-107 RS-422 Device
(1) T+ --------------------- R+
(2) T- ---------------------- R(3) R- ---------------------- T(4) R+ --------------------- T+
3.22 ATC-107 connecting RS-485 Device
RS-458 mode
ATC-107 RS-485 Device
(1) 485+ ---------------- 485+
(2) 485- ------------------485-
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