Isolated RS-232 to RS-485 Converter

Most industrial computer systems provide standard RS-232 serial ports with limited transmission speed, range, and networking capabilities. The RS-485 standards overcome these limitations by using differential voltage lines for data and control signals. The tM-7520U transparently converts RS-232 signals into isolated RS-485 signal with no need to change any hardware or software. This lets you easily build an industrial grade, long-distance communication system using standard PC hardware. The module provides 2500 VDC of optical isolation allowing you to separate and protect critical segments of the system from the rest of the RS-485 network.

The tM-7520U 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 Self-Tuner design is exactly the same as I-7520 series. The Fixed baud rate mode offers a better quality for data transmission over long or lossy lines or electrically noisy environments.


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    • 2-way 2500 VDC Isolation Protection
    • ESD Protection for RS-485 Data Line
    • Power Input, +10 ~ +30 VDC
    • Low power consumption
    • Long-cable application
    • Power and data flow indicator for troubleshooting
    • Easy-to-use rotary switch for baud rate setting, 1200 ~ 115200 bps
    • Operating Temperatures, -25 °C ~ +75 °C
    • Tiny packaging fits on your DIN-Rail


    Comparison Table of Repeater

    Models tM-7520U I-7520
    RS-485 Direction Control Fixed baud rate setting and Automatic RS-485 Direction
    Control (Self-Tuner, default)
    Automatic RS-485 Direction Control (Self-Tuner)
    Baud rate 300 ~ 115200 bps for Self-Tuner
    1200 ~ 115200 bps for Fixed baud rate setting
    300 ~ 115200 bps
    Dimensions (W x H x D) 52 mm x 92 mm x 27 mm 72 mm x 118 mm x 35 mm
    Remarks Entry-level
    Long-cable application

    Hardware Specifications

    Input RS-232: TxD, RxD and GND
    Output RS-485: Data+, Data-
    RS-485 Bias Resistor Yes, 1 KΩ
    Node 254 (max.)
    Transfer Distance Max. 1,200 m at 9.6 kbps; Max. 400 m at 115.2 kbps
    (Belden 9841 2P twisted-pair cable, if different cables are used, the transmission distance may change)
    2500 VDC Isolated Protection Yes
    Connection Removable 4-Pin Terminal Block x 1; 9-Pin Female D-Sub x 1
    LED Indicators
    Power/TxD/RxD Yes
    Input Voltage Range +10 VDC ~ +30 VDC (Non-isolated)
    Power Consumption 0.5 W
    Operating Temperature -25 °C ~ +75 °C
    Storage Temperature -30 °C ~ +75 °C
    Humidity 10 ~ 90% RH, non-condensing

    Ordering Informations

    tM-7520U CR Isolated RS-232 to RS-485 Converter (RoHS)
    tM-7520U-CA CR tM-7520U CR with CA-0915 cable x 1 (RoHS)