A1000 & A2000 USERS MANUAL 4
A 1 0 0 0 / 2 0 0 0 R S - 2 3 2 D B - 9 C O N N E C T O R
The A1000 and A2000 contain a female DB-9 connector normally used
with modems or other Data Communications Equipment (DCE).This
connector should be connected to a host computer, or controller, when
converting RS-232 signals to RS-485. The Transmit, Receive and
Ground signal lines are all that is required for proper RS-232-to-RS-485
operation. The remaining RS-232 flow control signals Carrier Detect (CD),
Data Set Ready (DSR) and Clear to Send (CTS) are internally biased to
their ACTIVE, or high, using 330 Ohm resistors connected to +10Vdc.
The RS-232 connector pinout is listed below.
Pin #
Description
1
(CD)
CARRIER DETECT
2
(TX)
TRANSMIT DATA
3
(RX)
RECEIVE DATA
4
(NC)
NO CONNECTION
5
(GND)
SIGNAL GROUND
6
(DSR)
DATA SET READY
7
(NC)
NO CONNECTION
8
(CTS)
CLEAR TO SEND
9
(NC)
NO CONNECTION
The RS-232 connector is left open when the A1000 or A2000 is used as
an RS-485 Repeater.
The only connections normally required for proper A1000 operation are
pins 2, 3 and 5 of the DB-9 connector. DB-9 to DB-25 adapters can be
made using the connections below.
DB-9 Pin #
DB-25 Pin #
2
3
3
2
5
7
A 1 0 0 0 / 2 0 0 0 R S - 4 8 5 I N C O N N E C T O R
The A1000 and A2000 converters contain a four-pin screw-terminal plug
labelled RS-485 IN. This connector is considered the HOST input when
using the A1000 or A2000 as a RS-485 repeater. An RS-485 repeater is
necessary to extend the length of an RS-485 network, or connect more
than 32 RS-485 devices on an RS-485 network.
The RS-485 IN data lines should be attached to the end of an existing
RS-485 network. The serial data received on the RS-485 IN data lines will
be reamplified and retransmitted on to the RS-485 OUT connector data
lines.
