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A green PCMCIA Type II card with two DB9 serial ports on the rear bracket

SerialGear

SerialGear SG-RS2SIS Dual Port RS-422/485 PCMCIA Card

SKU CH-QS02-0AC58

Adds two isolated RS-422/485 serial ports via a 32-bit CardBus or 16-bit PCMCIA 7.1 slot with 16C950 UARTs and auto transceiver turn-around up to 921.6 Kbps

  • External connectors2 x Serial Ports
  • Two 16C950 UART serial ports for reliable PCMCIA expansion
  • RS-485 auto transceiver turnaround via ATTA hardware simplifies wiring
  • Isolated surge-protected ports support 4-wire RS-422/485 and 2-wire RS-485
  • Data rates up to 921.6 Kbps for fast serial communication
  • 32-bit CardBus Type-II with 16-bit PCMCIA 7.1 backward compatibility

Dual Port RS-422/485 PCMCIA Card

The SerialGear SG-RS2SIS adds two isolated serial ports to any system with a 32-bit CardBus Type-II or 16-bit PCMCIA R7.1 slot. It targets engineers and technicians who need reliable RS-422 or RS-485 connectivity for industrial equipment, data acquisition, or legacy device integration. Plug-and-play installation removes the need for manual I/O address, IRQ, or DMA configuration.

Isolated Port Protection and ATTA Hardware

Each port uses a 16C950 UART and provides galvanic isolation plus surge protection for 4-wire RS-422/485 and 2-wire RS-485 wiring. The proprietary ATTA hardware automates RS-485 transceiver turn-around, eliminating software timing overhead and reducing bus contention in multi-drop networks. Drivers install automatically through the standard Install Wizard on supported operating systems.

Speed Headroom and Legacy Compatibility

The card sustains RS-422/485 signalling up to 921.6Kpbs, giving ample bandwidth for most industrial fieldbus and instrumentation tasks. Backward compatibility with the 16-bit PCMCIA R7.1 standard lets it serve older laptops and thin clients alongside newer CardBus platforms. Systems without a PCMCIA or CardBus slot cannot use this adapter, and applications requiring more than two simultaneous serial channels will need additional hardware.

How it compares

Measured against everything we stock in PCIe Expansion Cards, at today’s prices. Recalculated every night.

Price $125.99
Pricier than about 88% of the 891 comparable items (median $30.99).

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Specifications

Product
Model nameSG-RS2SIS
Ports & slots
External connectors2 x Serial Ports

Questions about this item

Will the isolated 16C950 UART ports need driver updates or hardware replacement after extended use in RS-422/485 applications?

The card uses standard 16C950 UARTs with plug-and-play drivers that install automatically via the Install Wizard; no jumper or I/O address configuration is required, so ongoing maintenance is limited to normal driver updates through the operating system.

What throughput ceiling appears first when both ports run continuously at 921.6 Kbps over RS-422/485?

Each port is rated for 921.6 Kbps and the CardBus Type-II 32-bit interface provides ample bandwidth, so the serial line speed of 921.6 Kbps per port is the limiting factor under sustained load.

How much power does the isolated dual-port card draw and how hot does it get when left running all day in a PCMCIA slot?

The card draws power directly from the PCMCIA slot and includes isolation and surge protection; with no active cooling or fan, heat output is low and typical of passive serial expansion cards in continuous operation.

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