Product Code : ACONSMD/E(U)
The RS232 to RS485/RS422 box provides bi-direction RS232 signals to RS485/RS422 signals conversion features, which are used to expand long haul distance communication for RS422 and multi-drop RS485 communication. The RS232 to RS485/RS422 box allows the input signals to be completely prevent up to 5000Vrms, which offers customers a unique combination of protection, speed, and versatility for industrial data communications applications. There are 3 LED indicators correspond to Tx, Rx, and power signals.

The features of the RS232 to RS485/RS422 box are:
EIA RS232 to EIA RS485/RS422 isolator input and output.

Heavy-duty optical couplers and a transformer isolated DC-to-DC converter to provide significantly higher electrical isolation - 5000V DC surge (1 minute), 5000V rms continuous.

Support Tx, Rx, RTS, CTS, SG signals for RS232, Tx+, Tx-, Rx+, Rx-, SG signals for RS422, and TRD+, TRD-, SG signals for RS485.
Communication speeds up to 230 K bps.
Transmit distance up to 4000ft.
Three LED indicators correspond to Tx(green), Rx(yellow), and power(red) signals.
250mA, 9 VDC  power input.
Life expectancy for relay: 100 million operations at signal level load.
Allow the photo input signals to be completely floated and prevent the ground loops.
Operating temperature from 0C° to 70C°.

Check that your RS232 to RS485/RS422 package includes the following items:
RS232 to RS485/RS422 box.
User manual.
Warranty form.

Hardware configuration:
The on boards jumpers can be used to set RS422/RS485 mode and select delay transmit time.

JP1 (Jumper 1) 

Select delay transmit time.

JP2 (Jumper 2) 

Select auto flow control.

JP3 (Jumper 3) 

Select RS422 or RS485mode.

The RS232 to RS485/RS422 box is shown in the following:

1.  Select RS422 or RS485 Mode
The JP1 is used to select RS422 or RS485 for port 2. To short pin means select RS485 mode.

Jumper Mode
Short RS485
Open RS422

2.  Select Auto Flow Control
The JP2 is used to select auto flow control. To short 2,3 means auto flow control, user only need to send data from Tx signal, the hardware will control RTS signal automatically. To short 1,2 means select RTS flow control, while user need to send data, it needs to set RTS to 1, to enter driver mode, then send message or data. After sending message, it needs to set the signal to 0 to enter receive mode again. The auto flow control is work for RS485 mode.

Enable by RTS Receive always enable
Short 1,2 Short 2,3

3.  Select Delay Transmit Time
The JP1 is used to select delay transmit time. To short the pin 1 and pin 2 means delay 4.6ms transmit time, and short the pin 2 and pin 3 means delay 40ms transmit time.

Jumper Delay Time
Short 1,2 4.6ms
Short 2,3 40 ms

1. DB25 Female Connector for RS232

Pin # Signal Name

  1  Chassis Ground(GND) AA  Common
  2  Transmit Data(TxD)
BA Output
  3  Receive Data(RxD) BB Input
  4  Request to Send(RTS) CA Output
  5  Clear to Send(CTS) CB  Input
  7  Signal Ground(SG)
AB Common

2. DB25 Male Connector for RS422

Pin Description
1     Chassis Ground
2     Transmit Data+(TxD+)
3     Receive Data+(RxD+)
6     Receive Data-(RxD-)
7     Signal Ground(SG)
20     Transmit Data-(TxD-)

The applications of RS232 to RS422 conversion are shown in the following:

a. Connect to RS422 Device

b. For Long Haul Distance Communication

3. DB25 Male Connector for RS485

1         Chassis Ground
2         Transmit Data+/ Receive Data+(TRD+)
20         Transmit Data-/Receive Data-(TRD-)
7         Signal Ground

The applications of RS232 to RS485 conversion are shown in the following:

a. Connect to RS485 Device

b. For Long Haul Distance Communication

Device Driver
Data Acquisition
Serial Technology

Test Tool & Sample Code
UARTs & Line Driver