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Grey rectangular adapter with four DB-9 ports and USB plug, LED indicators visible

SerialGear

SerialGear USB-4COM 4-Port USB DB-9 Serial Cable

SKU CH-M8DM-BM589

Adds four RS-232 DB9 serial ports via one USB 1.1 or 2.0 connection with 921.6K bps speed and 10KV surge protection

  • Connector count4
  • Product colorGray
  • DetailsSerial Modes: RS232
  • Adds four RS-232 DB9 ports via one USB connection
  • Rugged plastic housing with TxD and RxD LED status indicators
  • Full RS-232 modem control signals with hardware and software flow control
  • High-speed serial communication up to 921.6K bps baud rate
  • Surge protection of 10KV safeguards each serial port

Four RS-232 ports from one USB connection

The SerialGear USB-4COM adapter adds four DB-9 serial ports to a computer through a single USB 1.1 or 2.0 port. Each port supports RS-232 signalling at up to 921.6K bps with full modem control and hardware or software flow control. Rugged grey plastic housing includes TxD and RxD LED indicators. The device installs as standard Windows COM ports on Windows 7, 8, 10, Linux and Mac OS 10.x.

Suits industrial, retail and data-collection setups

Engineers who need to connect modems, PDAs, POS terminals, serial printers or legacy data-collection gear will find the four ports convenient. Surge protection of 10KV on each serial port helps in noisy environments. The adapter is not for systems without a USB 1.1 or 2.0 host port, nor for applications that require signalling standards other than RS-232.

RS-232 at 921.6K bps over USB 1.1 or 2.0

The single decisive specification is the maximum baud rate of 921.6K bps on each of the four RS-232 ports while connected through a USB 1.1 or 2.0 host port. If your equipment demands a higher rate or a different serial protocol, this adapter will not meet the requirement.

How it compares

Measured against everything we stock in RS-232 Serial Cables, at today’s prices. Recalculated every night.

Price $89.99
Pricier than about 90% of the 93 comparable items (median $21.99).

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Specifications

Product
Brand nameSERIALGEAR
Model nameUSB-4COM
Product colorGray
Ports & slots
Connector count4

Questions about this item

Does the USB-4COM adapter need an external power supply or does it draw power from the USB port?

The adapter is bus-powered and draws all required power from the host USB 1.1 or 2.0 port, so no external power supply is needed.

Which driver package should be installed on Windows 10 so the four DB-9 ports appear as standard COM ports?

Install the SerialGear Windows driver; after installation each port registers as a standard COM port and the COM number can be reassigned in Device Manager to any value required.

The DB-9 connectors list 10 kV surge protection — does that component degrade and need periodic replacement?

The 10 kV surge protection is built into the port circuitry and is not a user-replaceable part; no scheduled maintenance or replacement is required for the adapter itself.

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