MB5201DB 1-port RS-232/422/485(DB9) Modbus Gateway

MB5201DB 1-port RS-232/422/485(DB9) Modbus Gateway


Modbus TCP to Modbus ASCII/RTU converter gateway allows Modbus TCP masters to communicate with serial Modbus slave devices via RS-232/RS-485/RS-485 interfaces.

  • Manufacturer: ATOP
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  • $179.05
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The Atop MB5201 series provides an interface between Modbus serial slave devices and hosts running Modbus/TCP on Ethernet networks. This low power, compact device is housed in a metal casing making them ideal for interfacing industrial equipment such as PLCs, HMIs, various sensors and measuring instruments. User friendly setup via a web based UI ensures simple integration even for complex configurations.

The MB5201 series supports the three most commonly used serial communication interfaces, RS-232, RS-422 and RS-485. It also provides a web-based configuration UI, so the users can select the serial interface easily.


  • 1 x software-selectable RS-232/485/422 port
  • 1 x 10/100Mbps RJ45 Fast Ethernet port
  • Supports TCP server/client, UDP, Virtual COM and Tunneling modes
  • Modbus TCP/RTU/ASCII
  • Configuration via Web Server page, Telnet Console, and Windows Utility
  • Upgradable firmware via Ethernet from a remote-PC
  • Rugged metal casing; industrial EMC protection
  • Redundant dual DC power inputs for non-stop operation
  • Optional DIN-Rail mounting


  • Input: 5 VDC (DC-Jack) or 9 to 30 VDC (screw terminals) 
  • Consumption: ≤1.5 W 


  • Interface: RS-232/422/485 software selectable 
  • Ports: 1
  • Baud rate: 120 bps to 230 Kbps
  • Parity: None, odd, even, mark, space
  • Data bits: 7,8
  • Stop bits: 1,2
  • Flow control: 
    • None
    • Software: Xon/Xoff
    • Hardware: RTS/CTS 
  • Protection: 15 kV ESD 
  • Connector: 5 pin Terminal Block


  • Transmission rate: 10/100M Auto-detection 
  • port(s): 1
  • Connector: RJ-45
  • Compliance: IEEE802.3
  • Auto MDI/MDI-X: Yes

Link Mode

  • Modbus TCP: Yes
  • Modbus ASC: Yes
  • Modbus RTU: Yes


  • Configuration: Web Page / Telnet / CLI
  • Atop tool: Atop Management Utility
  • Support protocol: TCP, IPv4, UDP, DHCP Client, HTTP, HTTPS, Telnet, ARP, SNMPv1,v2c,v3  


  • Operating temperature: -40°C ~ 70°C (-4°F ~ 158°F)  
  • Storage: -40°C ~ 85°C (-40°F ~ 185°F) 
  • Dimensions: 65mm x 78mm x 28mm (without wall-mount part)


  • EMC: FCC Class A, CE Class A 


  • Preceding: 57.5 years (25 °C) 
  • Report: Yes


  • W x H x D: 65 x 28 x 78 mm
    • SKU
    • Weight
      0.18 kg
    • Dimensions (L x W x H)
      20 x 16 x 8 cm

Faulty Goods and Warranty

Where such goods have been supplied we undertake to repair or replace them as quickly as possible.Prior to returning faulty items, please contact us with a description of the fault as one of our engineers might be able to assist you by resolving the issue over the phone.
A Warranty form must be filled out and returned with any goods.

Our standard warranty period is 12 months from the date of purchase unless stated otherwise.

Other warranty periods:

Labjack Products: 5 Years
Atop Products: 3 Years
MeanWell Products: 3 Years
Terracom Products: 3 Years

Warranty is subject to us being satisfied that a defect was caused by defective workmanship or materials and was not caused by or was not substantially contributed to by other factors beyond our control including incorrect installation, alterations or modifications of the product not recommended by the manufacturer.

Returns Policy

If you are dissatisfied with our goods you may return them within 14 days of the dispatch date. Contact us for an authorisation and we will refund your purchase less shipping costs and restocking fees. All returned goods MUST be in AS NEW condition including ALL PACKAGING and DOCUMENTATION / MANUALS etc.

Please note:

  • The product returned will attract a 20% restocking fee.
  • The customer must pay the delivery costs.
  • Non standard, custom made or a specially manufactured or imported products are not returnable.
  • Semiconductors, books and software are not refundable

Full Terms and Conditions

By placing an order with Ocean Controls, you agree to be bound by our Terms and Conditions of Trade.

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