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Serial Communication Products

Many types of external computer equipment have a serial ports to communicate with host PCs. ACCES I/O has Communication Cards for all of the popular protocols you may find on this type of equipment (RS-232, RS-422 and RS-485), ranging from a single port to eight ports on a single card. There are also optically isolated versions of some of these cards to ensure effective data transmission on long communication lines, even in electrically noisy environments. Having optical isolation is like having data insurance.

RS-485 and RS-422 have significant advantages over RS-232 as they use differential drivers instead of driving just one wire. This allows the cables in RS-485 and RS-422 applications to be up to 4000 feet, where RS-232 has a limit of 50 feet. See the table below for a comparison of cable length vs. baud rates.

PCI Express Serial Communication Cards
 SERIAL PORTS
ProductsRS-232RS-422RS-485BaudPROT CFGISOLATIONLRG FIFOConnectorRoHS
PCIe-COM-8SM*8 Software Selectable921.6k3EEPROM128-ByteCabled DB9
PCIe-COM485-8*8921.6k3EEPROM128-ByteCabled DB9
PCIe-COM422-8*8921.6k3EEPROM128-ByteCabled DB9
PCIe-COM232-8**8  921.6k128-ByteCabled DB9
PCIe-COM-4SM* 4 Software Selectable921.6k3EEPROM128-ByteCabled DB9
PCIe-COM-4SMRJ4 Software Selectable921.6k3EEPROM 128-ByteRJ45
PCIe-COM-4SMDB4 Software Selectable921.6k3EEPROM 128-ByteDB9
PCIe-ICM-4SM4 Software Selectable921.6k3EEPROMYes128-ByteDB9
PCIe-COM-4SRJ 4 Software Selectable921.6k3EEPROM 128-ByteRJ45
PCIe-COM-4SDB 4 Software Selectable921.6k3EEPROM 128-ByteDB9
PCIe-ICM-4S 4 Software Selectable921.6k3EEPROMYes128-ByteDB9
PCIe-COM485-4* 4921.6k3EEPROM128-ByteCabled DB9
PCIe-COM422-4* 4921.6k3EEPROM128-ByteCabled DB9
PCIe-COM232-4**4  921.6k128-ByteCabled DB9
PCIe-COM232-4RJ4  921.6k 128-ByteRJ45
PCIe-COM232-4DB4  921.6k 128-ByteDB9
PCIe-ICM232-44  921.6kYes128-ByteDB9
PCIe-COM-2SMRJ2 Software Selectable921.6k3EEPROM 128-ByteDRJ45
PCIe-COM-2SMDB2 Software Selectable921.6k3EEPROM 128-ByteDB9
PCIe-ICM-2SM2 Software Selectable921.6k3EEPROMYes128-ByteDB9
PCIe-COM-2SRJ 2 Software Selectable921.6k3EEPROM 128-ByteRJ45
PCIe-COM-2SDB 2 Software Selectable921.6k3EEPROM 128-ByteDB9
PCIe-ICM-2S 2 Software Selectable921.6k3EEPROMYes128-ByteDB9
PCIe-COM232-2RJ2  921.6k 128-ByteRJ45
PCIe-COM232-2DB2  921.6k 128-ByteDB9
PCIe-ICM232-22  921.6kYes128-ByteDB9
PROT CFG = protocol configuration * Low Profile MD2 PCI/PCIe spec ** Low Profile MD1 = Smallest PCI/PCIe specification = Optionally available RoHS Ready 3 = Up to 3Mbps with custom software

PC/104 (ISA only) Serial Communication DAQ Products
  SERIAL PORTS OPTIONS
Products RS-232 RS-422 RS-485 Baud PROT CFG ADDR CFG LRG FIFO XT
104-COM232-22  230.4k JumperYesYes
104-COM232-44  230.4k JumperYesYes
104-COM232-88  230.4k JumperYesYes
104-COM-2S 22921.6kJumperJumperYesYes
104-ICOM-2S* 22115.2kJumperJumperYesYes
104-COM-2SM222921.6kJumperJumperYesYes
104-COM-4S 44921.6kJumperJumperYesYes
104-COM-4SM444921.6kJumperJumperYesYes
104-COM-8S 88921.6kJumperJumperYesYes
104-COM-8SM888921.6kJumperJumperYesYes
PROT CFG = protocol configuration   XT = extended temperature option   * optically isolated and optional 460.8k baud rate

PCI-104 (no ISA connector) and PC/104-Plus (ISA, PCI) Serial Communication DAQ Products
  SERIAL PORTS OPTIONS
Products RS-232 RS-422 RS-485 Baud PROT CFG ADDR CFG LRG FIFO XT
104I-COM232-22  460.8k SoftwareYesYes
104I-COM232-44  460.8k SoftwareYesYes
104I-COM232-88  460.8k SoftwareYesYes
P104-COM232-8*8  460.8k SoftwareYesYes
104I-COM-2S 221.8432MbpsJumperJumperYesYes
104I-COM-2SM2221.8432Mbps**JumperJumperYesYes
104I-COM-4S 441.8432MbpsJumperJumperYesYes
104I-COM-4SM4441.8432Mbps**JumperJumperYesYes
104I-COM-8S 881.8432MbpsJumperJumperYesYes
104I-COM-8SM8881.8432Mbps**JumperJumperYesYes
PROT CFG = protocol configuration   XT = extended temperature option  
*PC/104-Plus (PCI and ISA connector)   **Up to 921.6k RS-232

PCI Bus Serial Products
 SERIAL PORTSOPTIONS
ProductsRS-232RS-422RS-485BaudPROT CFGLOW PROFLRG FIFORoHS
LPCI-COM-1S 11460.8kJumperYesYes
PCI-ICM-1S* 11460.8kJumper Yes
PCI-ICM-2S* 22460.8kJumper Yes
PCI-422/485-2 22460.8kJumper Yes
PCI-COM-2S222460.8kJumper Yes
PCI-COM232/22  115.2kFixed  
PCI-COM232/44  115.2kFixed  
LPCI-COM232-44  921.6kFixedYes 
LPCI-COM-4SM444921.6kJumperYes 
PCI-COM422/4 4 460.8kFixed Yes
PCI-ICM422/4* 4 460.8kFixed Yes
PCI-COM485/4  4460.8kFixed Yes
PCI-ICM485/4*  4460.8kFixed Yes
LPCI-COM232-88  921.6kFixedYes 
LPCI-COM422-8 8 921.6kFixedYesYes
LPCI-COM485-8  8921.6kFixedYesYes
LPCI-COM-8SM888921.6kJumperYes 
PROT CFG = protocol configuration | LOW PROF = low profile form factor
* optically isolated | = Optionally available RoHS Ready

Serial Converter Products
MODELDESCRIPTIONRoHS
CONV232/485RS-232 to RS-485 Serial Communications Adapter
CONV232/422RS-232 to RS-422 or four-wire RS-485 Serial Communications Adapter

USB Serial Products
MODELDESCRIPTIONRoHS
USB-232,
USB-422
and USB-485		Add a single RS-232, RS-422 or RS-485 serial port to any USB equipped computer
USB-COM-2SMTwo-port USB to serial RS-232/422/485 adapter
USB-FLEXCOM4Four-Port Serial Communications adapter for Universal Serial Bus
USB-COM232-4AFour-Port Serial RS-232 Communications adapter for Universal Serial Bus
USB-IIRO4-2SMTwo-Port USB to Serial RS-232/422/485 adapter with 4 Electromechanical relays and 4 optically isolated inputs.

Ethernet Serial Products
MODELDESCRIPTIONRoHS
eNET-232-1Single-Port Ethernet-to-Remote RS-232 Serial Interface Device
eNET-422-1Single-Port Ethernet-to-Remote RS-422 Serial Interface Device
ETH-01
New Product!		Single-Port Ethernet-to-Remote RS-422/-485 Embeddable / OEM Serial Interface Module

Watchdog Products
MODELDESCRIPTIONRoHS
WDG-SIOWatchdog Timer and RS422/485 Serial Communications Card
WDG-2SWatchdog Timer and Dual RS422/RS485 Serial Communications Card

Baud Rate vs Cable Length*
Baud Rate Standard Divisor Divisor x4 Divisor x8 Maximum Differential Cable Length*
921600 - - 1 250 ft.
460800 - 1 2 500 ft.
230400 - 2 4 1400 ft.
153600 - 3 6 2500 ft.
115200 1 4 8 3000 ft.
57600 2 8 16 4000 ft.
38400 3 12 24 4000 ft.
28800 4 16 32 4000 ft.
19200 6 24 48 4000 ft.
14400 8 32 64 4000 ft.
9600 12 48 96 4000 ft.
4800 24 96 192 4000 ft.
2400 48 192 384 4000 ft.
1200 96 384 768 4000 ft.
*These are theoretical maximums based on typical conditions and good quality cables based on the EIA 485 and EIA 422 standard for balanced differential drivers.

Acquisition, Control, Communication: Engineering and Systems