Low Profile PCI Express 8-Port RS-422, RS-485 Serial Interface

Part: 7802e   Model: COMM+8.422.PCIE

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The 7802e low profile PCI Express serial interface provides eight serial ports, each individually field-configurable for RS-422 or RS-485 communications. The board uses 16C954 UARTs with 128-byte Tx/Rx FIFOs that enables data rates to 921.6K bps for reliable high-speed communications in data intensive applications. This high-performance UART includes 9-bit framing support and is register compatible with legacy 16550 software applications. In addition, the board derives a 62.5 MHz clock from the PCI Express link. This ultra-high speed clock is divided by a flexible 8-bit clock prescalar with 1/8 steps to provide support for the widest range of standard and non-standard baud rates.

In RS-485 mode the board provides automatic control of the RS-485 driver in hardware, eliminating the need for application software control. This allows the 7802e to be used with standard serial communications applications and removes the risk of bus contention and data corruption. Additionally, RS-485 network termination, critical to robust multi-drop communication, can be selectively added to the circuit via DIP-switches.

Sealevel SeaCOM software driver and utilities make installation and operation easy using Microsoft Windows and Linux operating systems.

The 7802e is a PCI Express X1 board compatible with any low profile PCI Express slot. A standard profile bracket  is also included. The board ships with a 36 inch cable that terminates to eight DB9M connectors.


Additional information

Operating Temperature

0°C to 70°C (32°F to 158°F)

UART Series

950 UART

Storage Temperature

-50°C to 105°C (-58°F to 221°F)

Serial Connector(s)


RoHS Compliant


# of Ports


PC Bracket

Low Profile, Standard Height

Board Connector


Max Data Rate

921.6K bps

Cable Connector(s)

DB9M (8)

Max Data Distance

4000 feet

Host Interface(s)

PCI Express

Humidity Range

10 – 90% Relative Humidity, Non-Condensing

Electrical Interface

RS-422, RS-485


4.700” (L) x 2.536” (H)

Communications Chip



62.5 MHz

  • Each port individually configurable for RS-422 or RS-485
  • 16C954 buffered UARTs with 128-byte FIFOs
  • Oscillator and clock prescalar support wide range of baud rates
  • Supports 9-bit protocol framing
  • Each port supports data rates to 921.6K bps
  • RS-485 line termination, pull-up and pull-down resistors for each port are selectable via dipswitch
  • RS-485 ECHO can be enabled/disabled via dipswitch
  • Automatic RS-485 enable/disable in hardware
  • PCI Express X1 compliant
  • Compatible with any low profile PCI Express slot. A standard profile bracket  is also included
  • Included 36″ cable terminates to eight DB9M connectors (Item# CA231)

Windows Software

Software: SeaCOM - Windows


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