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104i-COM-8SM Family

PCI-104 8-Port, 4-port, and 2-port Multi-Protocol RS-232, RS-422, RS-485 Serial Communication Boards


  • 8, 4, and 2-port PCI-104 serial communication boards
  • High performance octal PCI UART
  • Field selectable RS-232, RS-422, and RS-485 protocols, jumper configured per port
  • Speeds up to 1.8432Mbps in RS-422/485 modes (RS-232 up to 921.6 kbps)
  • 16550 compatible register set with 64-byte FIFO for each TX and RX
  • ±15kV ESD protection on all RS-232 signal pins
  • Full modem control signals in RS-232 mode
  • Auto-RTS feature makes half-duplex RS-485 communication effortless
  • Fixed bias and jumper selectable termination provided on each RS-422/485 transmit and receive channel
  • Software compatible with all operating systems as standard COM port
  • RS-485 full-duplex (4-wire) fully supported
  • RS-422/RS-485 only versions
  • Designed, made, supported, and manufactured in the USA


  • Extended temperature operation (-40°C to +85°C)
  • Fast RS-232 version up to 921.6k
  • RoHS Available. Please contact us for ordering information
The 104i-COM-8SM (PCI-104) family of multi-port, multi-protocol (RS-232, RS-422, RS-485), serial communication boards deliver up to eight high-speed serial communication ports for use in a wide variety of applications. The boards were developed for use by system integrators and manufacturers in the design of industrial and commercial systems. Based on the XR17D158, the boards have eight enhanced 16550 UARTs, each with a set of modem signals (CTS, RTS, RI, DTR, DSR, CD) in RS-232 mode. Each UART has both a 64 byte transmit and a 64 byte receive FIFO. Ports are accessed via two 40-pin IDC type right angle header connectors. 2 and 4-port versions are available, as well as RS-232 only models.

The 104i-COM-8SM Series are feature-rich and allow for the connection of multiple serial devices—ideal for a variety of applications such as POS, gaming systems, retail, hospitality, automation, kiosks, defense industries, high-density networking, or any other application requiring the connection of RS-232/422/485 serial devices to a PCI-104 compatible system. ACCES offers the 104i-COM-8SM, 4SM, and 2SM in both standard and extended temperature versions ideal for outdoor applications, harsh industrial surroundings, or military use.


Available accessories include a broad range of cable assemblies, screw terminal boards, adapters, and enclosure/system solutions for quick and easy embedded application setup.


Please contact ACCES with your precise requirement. Examples of special orders would be conformal coating, latching and/or right-angle I/O connectors, RJ45 connectivity, longer breakout cables, custom baud rates, custom software, etc... we will work with you to provide exactly what is required.


The 10I-COM-8SM family of boards are supported by all operating systems as standard serial ports. All boards include a free DOS, Linux and Windows XP -> 10, both 32 & 64 bit compatible software package with sample programs and source code in "C" and Pascal for DOS, and Visual Basic, Delphi, C#, and Visual C++ for Windows. Also provided is a graphical option configuration program in Windows. An easy-to-use Windows terminal program simplifies verification of proper operation. Linux support includes installation files and samples for register-level programming in "C".

Available Reference Manuals

Available Software Downloads

Available Datasheets

Drivers and Downloads

Full list of available Downloads: Software Packages, Drivers, Manuals, and other documents

Custom Software

ACCES also offers Custom Software Services for our products. Our prices are unbelievably low, often as inexpensive as free! If you need something tweaked to support your needs, or an entire enterprise application developed from scratch, it is definitely worth your time to inquire with us, first.

Further information about available ACCES Software:

Redistributing Windows Drivers
A list of ACCES drivers and the files that compose them under different versions of Windows, so you can easily redistribute ACCES cards and drivers.



  • PCI Bus: Rev. 2.3
  • Memory Space: Requires 4k
  • I/O connection: 40-pin headers 0.1” spacing x 2
  • Serial ports: 8, 4, or 2-ports, RS-232, RS-422, or RS-485, selectable

16550 Compatible

  • UART: Octal type 16C550 with eight 64-byte transmit & 64 byte receive FIFO, 16C550 compliant
  • Data Size: 5, 6, 7 or 8 bits
  • Stop bit length: 1, 1.5 or 2 bits
  • Parity: Odd, even, none, mark, or space
  • Flow Control: RTS/CTS and/or DSR/DTR, Xon/Xoff
  • Break condition: On or off
  • Maximum Baud Rate: 1.8432Mbps (RS-422 & RS-485 modes), 460.8Kbps (RS-232 mode standard model), 921.6kbps (RS-232 Fast (-F) factory option)
  • Full Duplex Operation
  • Software programmable FIFO trigger levels (16C550 trigger levels are fixed)
  • 12 standard registers for UART monitoring and control plus special registers
  • Loop-back mode
  • Scratch pad register

RS-232 Transceiver I/O Characteristics

  • Receiver Input Resistance: 3KΩ to 7KΩ
  • Receiver Input Sensitivity: ±3V
  • Receiver Input Voltage Range: ±15V
  • Driver Slew Rate: 30V/µS minimum
  • Driver Load Impedance: 3KΩ to 7KΩ
  • Driver Output Signal Levels: Loaded ±5.4V typical
  • Meets or exceeds the IEEE RS-232 standard

RS-422/RS-485 Transceiver I/O Characteristics

  • Receiver Input Sensitivity: ±200mV differential input
  • Common Mode Voltage Range: +12V to -7V
  • Transmitter Output Drive: 60 mA with thermal shutdown
  • Input Impedance: 12 K ohm Min
  • Input Hysteresis: 50mV typical

Transceiver ESD Characteristics

  • ±15kV Human Body Model
  • ±15kV Air Discharge
  • ±8kV Contact Discharge

Communications Interface

  • Eight channels split between two 40 pin male headers
  • Meets or exceeds the IEEE RS-232 standard


  • Operating Temperature Range:
    • Commercial: 0° to 70°C
    • Industrial: -40°C to +85°C
  • Humidity: 5% to 95%, non-condensing
  • Storage Temperature Range: -65°C to +125°C
  • Power Required: +5VDC, 50mA quiescent, 150mA maximum (nothing connected on I/O connectors)
  • Size: PCI-104 format, 3.5" x 3.75"

Regulatory Compliance

  • This product is designed to be in full compliance with CE requirements. CE testing & approval must be done at the system level, in the designed enclosure, and is not done on individual boards.

ModelPrice (USD)

Ordering Guide
104i-COM-8SMPCI-104 (no ISA connector) 8-port RS-232/422/485 serial communication board
104i-COM-4SMPCI-104 (no ISA connector) 4-port RS-232/422/485 serial communication board
104i-COM-2SMPCI-104 (no ISA connector) 2-port RS-232/422/485 serial communication board
104i-COM-8SPCI-104 (no ISA connector) 8-port RS-422/485 (no RS-232) serial communication board
104i-COM-4SPCI-104 (no ISA connector) 4-port RS-422/485 (no RS-232) serial communication board
104i-COM-2SPCI-104 (no ISA connector) 2-port RS-422/485 (no RS-232) serial communication board
C104-40F-D9M40 pin ribbon cable with female header to 4 DB9M connectors, 12" long $25
C104-40F-1240-pin ribbon cable with female headers, 12" long $12
C104-40F/D37F40 pin ribbon to DB37 female cable $17.50
C104-D37M/D9M3' round-wire breakout cable, male DB37 to four male DB9 connectors $31
UTBK-40RDirect connect 40-pin removable screw terminal board $49
STB-40Screw terminal board for 40 pin header type connector $44
ADAP9Screw terminal adapter (single DB9 female to 9 screw terminals) $19
ADAP9-2Screw terminal adapter (dual DB9 female to 18 screw terminals) $25
104-HDW-KIT(X)Specify metric (M) or standard (S) hardware kit. Includes 4 screws, nuts and standoffs $10
MP104-DINDIN-rail mounting provision $19
PCI-P104-ADAPPCI to PC/104-Plus adapter card permits a PC/104-Plus board to be installed in a PCI slot $129
104-BP2Backplane with two side-by-side 16-bit PC/104 connectors $99
Options (call for pricing)
-TExtended operating temperature (-40°C to +85°C)
-FFast version (RS-232 up to 921.6kbps)
-RoHSRoHS compliant version
-CallContact ACCES with your special requirement

Acquisition, Control, Communication: Engineering and Systems