RS485-RS232 Hub

RS485-RS232 Hub


Introduction RS-485 Active Hub

The I-7520U4 is isolated RS-232 to 4-ch RS485  active star wiring hub, which has 4 independent RS-485 output channels and one RS-232 input channel. Each output channel is equipped with an individual driver. The data from a master to the input channel will simultaneously be forwarded to all the four output channels.

Baud Rate Setting

The I-7520U4 provides 2 modes of baud rate setting, one is Self-Tuner mode and the other is fixed baud rate mode. The Self-Tuner mode can support Multiple Baud Rate and Multiple Data Format. The Fixed baud rate mode offers a better quality for data transmission over long or lossy lines or electrically noisy environments.

RS-485 Short-circuit

The Short-circuit protection can automatically shut off the breakdown channel, this kind of design can suffice to protect the communication system. When connected RS-485 equipment breaks down, the breakdown channel will be isolated to ensure that other equipments work normally.

Termination Resistors

In some critical environments, you may need to add termination resistors to prevent the reflection of serial signals. The I-7520U4 includes a 120Ω termination resistor for each channel by jumper selectable.

LED Indicators

The I-7520U4 has 6 LED to indicate the power status and network traffic. The TxD/RxD LED will flash when the unit is being sent out or received data.


Input 1 RS-232 Channel: TxD, RxD, GND
Output(Slave) 4 Rs-485 Channels: Data+, Data-
2-wire Cabling Belden 8941 (2P twisted-pair cable), if different cables are used, the transmission distance may change
Transfer Distance
MAX  Devices Supported
MAX 1200m at 9.6 kbps; Max 400m at 115.2 kbps
256 (Each Channel)
Self-Tuner Asic Inside Yes
Speed 300~115200 bps via Self-Tuner mode; 1200 ~ 115200 bps via Fixed Baud Rate mode
ESD Protection Yes
2500 VDC isolation on RS-232 Yes
Connection Removable 10-Pin Terminal Block x 1; 9-Pin Female D-Sub x 1
LED Indicators
Power/Communication Yes
Input Voltage Range +10 VDC ~ +30VDC (Non-isolated)
Power Consumption 1.2W
Casing Plastic
Flammability Fire Retardant Materials (UL94-V0 Level)
Dimmensions (WxHxD) 72mm X 118mm X 35mm
Installation DIN-Rail
Operating Temperature -25 oC ~ +75 oC
Storange Temperature -30 oC ~ +80 oC
Humidity 10 ~ 90% RH, non-condensing

Dimensions (mm)

Pin Assignments

Terminal No. Pin Assignment Pin Assignment Terminal No. Pin Assignment
RS-485 01 D1+ CH1
02 D1-
03 D2+ CH2 ISO.GND 05
04 D2- 04
05 D3+ CH3 RxD 03
06 D3- TxD 02
07 D4+ CH4 01
08 D4-
09 (R)+Vs RS-232: Female DB-9 Connector
                10 (B)GND