DTech DT-9003 User manual

DT-9003
Commercial grade interface converter
Manual
I. Overview
The Converter is compatible with the RS-232,
RS-485 standard. RS-232 signal is converted to RS485 or
RS422 balanced differential signal; no need of external
power supply, it adopts the unique "RS-232 charge
pump" to drive the whole circuit inside; there is zero
delay automatic transceiver conversion device in the
circuit, and I/O circuit prevents collision to automatically
control data flow direction, thereby it ensures that the
program written on RS232 mode is no need to be
changed and safely be operated in RS485 or RS422 mode,
fully ensure it’s compatible with for existing software
and hardware interface.
II. Performance parameter
1. Interface characteristics: compatible with EIA/TIA RS-232C,
RS-485/RS-422 standard
2. Electrical interface: DB9 female connector at RS-232 end, DB9
male connector at RS485/RS422 end, with 6 position terminal
board
3. Working mode: Asynchronous Full Duplex, half duplex
automatic selection of differential transmission, without jumper
settings
4. Transmission medium: twisted pair wire or shielded wire
5. Transmission rate: 300BPS-115.2KBPS
6. Size: 64mmX33mmX17mm
7. Use of the environment: -20 degrees to 70 degrees, relative
humidity of 5% to 95%
8. Transmission distance: 1200 meters (RS-485 end), 5 meters
(RS-232 end)
III. Connector and Signal
RS-232C pin-out
DB9 Female (Pin)
RS-232C Interface signal
1
Protective Grounding
2
Receive data SIN (RXD)
3
Send data SOUT (TXD)
4
Data terminal ready (DTR)
5
Ground signal (GND)
6
Data setting ready (DSR)
7
Request send (RTS)
8
Clear send (CTS)
9
Ring indication RI
RS-485 /RS-422 output signal and pin-out of terminal board
IV. Hardware installation and application
The product is designed with universal adapter plug DB9 M /
DB9 F. Its output interface comes with a terminal block, which is
connected with twisted pair or shielded cable, making it quite
convenient for either connection or dis-assembly. T/R+, T/R-
stands for receiving / sending A+ B-, GND stands for Ground.
VCC stands for Positive Supply voltage.
In RS-485 half duplex connection mode, connecting T/R+
(send / receive +) to opposite side’s A+ and T/R- (send / receive -)
to opposite side’s B-; In RS-422 half duplex connection mode,
connecting T/R+ (transfer+) to opposite side’s RXD+ (receive+),
DB9 Male
Single output
RS-422 Full
duplex
RS-485 Half
duplex
1
T/R+
Send(A+)
RS-485 (A+)
2
T/R-
Send (B-)
RS-485 (B-)
3
RXD+
Receive(A+)
N/C
4
RXD-
Receive (B-)
N/C
5
GND
Ground wire
Ground wire
6
VCC
Power
Power

T/R- (transfer-) to opposite side’s RXD- (receive-),
RXD+(receive+) to opposite side’s TXD+(transfer+), RXD-
(receive-) to opposite side’s (transfer-).
Communication mode supported:
①Point to point / Four line full duplex
②Point to multi-point / four line full duplex
③Point to point / two line half duplex
④Point to multi-point / two line half duplex
Note: to avoid signal reflections and interference, a matched
termination resistor (120Ω，1/4W) is required to wired at the
terminal of the line according to particular situation
Please be noted: this converter is port-powered, so normally
external power supply is not required. If you need it as your case
may be, the pin of VCC allows you to connect a 9V external power
supply to it.
V. Communication Wiring Diagrams
RS-232 TO RS-422 Conversion
VI. Troubleshooting
1. communication failure
A. Check to see if RS-232 interface connection is correct
B. Check to see if RS-485 output interface wiring is correct
C. check to see if the wired terminal board is connected well

2. data loss or error
Check to see if data rate and format at both ends of the
communication equipment are consistent
3. Unstable Signal
Wired a matched termination resistor at RS485 end or replace it
with an active RS232 to RS485 converter