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Black rectangular metal box with four DB-9 ports and a USB cable

SerialGear

SerialGear CS-42042 4-Port USB to DB-9 RS-232 Converter

SKU CH-NR0V-YFGVB

Adds four DB-9 RS-232 serial ports via USB with FTDI chipset, 75 to 921.6 Kbps rates and a rigid metal case

  • Adapter typeUSB to DB9 (RS-232)
  • Product colorBlack
  • Four RS-232 ports from one USB connection
  • Data rates from 75 bps to 921.6 Kbps supported
  • USB 1.0, 1.1 and forward compatible with 2.0
  • Rigid metal case built for critical applications
  • Plug-and-play setup needs no manual IRQ or I/O config

Four-Port RS-232 Expansion

The SerialGear CS-42042 adds four DB-9 male serial ports to a PC, thin client or server through a single USB connection. It targets engineers and integrators who need to attach legacy RS-232 equipment such as industrial controllers, laboratory instruments or networking gear to modern systems that lack native COM ports.

921.6 Kbps Headroom

Each port handles asynchronous data rates from 75 bps up to 921.6 Kbps using three-wire TXD, RXD and GND signalling. The FTDI chipset supports multiple modules on one USB 1.0 or 1.1 bus and remains forward compatible with USB 2.0 hosts, so bandwidth scales with the number of active ports rather than saturating at a single port’s maximum.

Replaces ISA/PCI Serial Cards

This adapter removes the need for internal expansion cards, IRQ jumpers or I/O address configuration by moving the serial interface to USB plug-and-play. The rigid metal enclosure suits surface-mount installations in cabinets or DIN-rail environments where full-height cards cannot fit. It is not suited for applications that require full modem-control handshake lines beyond TXD, RXD and GND.

How it compares

Measured against everything we stock in USB Adapter Cables & Dongles, at today’s prices. Recalculated every night.

Price $94.99
Pricier than about 91% of the 1,430 comparable items (median $14.99).

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Specifications

Product
Brand nameSERIALGEAR
Model nameCS-42042
Product colorBlack
Adapter typeUSB to DB9 (RS-232)

Questions about this item

Will the CS-42042 work with my existing USB 1.0 or 1.1 hubs, or do I need USB 2.0?

The adapter is fully compatible with USB 1.0 and 1.1 and works forward-compatible with USB 2.0, so it will operate on any of those host ports.

How can I verify each of the four DB-9 ports is communicating at the correct baud rate after installation?

Open Device Manager, check that four new COM ports appear, then use a terminal program to test TXD, RXD and GND signals at rates between 75 and 921.6Kbps.

Does the CS-42042 package include the USB cable and driver media, or must I source them separately?

The rigid metal case houses four DB9 male ports and connects via a standard USB interface; driver installation follows the on-screen Install Wizard, so no separate media is required.

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