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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 Bus Serial Products
 SERIAL PORTSOPTIONS
ProductsRS-232RS-422RS-485BaudPROT CFGLOW PROFLRG FIFORoHS
PCIe-COM232-8
New Product!		8  921.6kMD1*Yes
PCIe-COM232-4
New Product!		4  921.6kMD1*Yes
PCIe-COM-8SM
New Product!		8 Software Selectable921.6kEEPROMYesYes
PCIe-COM-4SM
New Product!		4 Software Selectable921.6kEEPROMYesYes
PCIe-COM-8S
Coming Soon!		8 Software Selectable921.6kEEPROMYesYes
PCIe-COM-2SM
In Development!		2 Software Selectable921.6kEEPROM Yes
PROT CFG = protocol configuration LOW PROF = low profile form factor * MD1 = smallest PCI/PCIe low-profile specification = Optionally available RoHS Ready
PC/104 Bus Serial 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
P104-COM232-88  460.8k SoftwareYesYes
104-COM-2S 22115.2kJumperJumperYesYes
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

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

PC-Card / PCMCIA Serial Products
MODELDESCRIPTIONRoHS
PCM485PCM485 PCMCIA RS-422/485 Serial Communications Card

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
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