Re: DSC 864 Serial Cable Length

["A.J." <aj@xxxxxxxx>]

Serial Cable Length Limits (RS232, V.35,  RS530, RS422/449)
SCSI Cable Length Limits
Parallel Cable Length Limits


Serial Cable Length Limits (RS-232, V.35,  RS-530, RS-422/449)

Table below lists the maximum permissible cable lengths for various
protocols  at various  representative data rates. These lengths are as
specified in the EIA RS232C, CCITT V.55 and RS422 interface standards.

Material requirements:

      * Conductor size and type: 24 AWG, twisted pair.
      * Nominal capacitance: 15.5 picofarads per foot (between
conductors of each pair);
        27.5 picofarads per foot (from each conductor to shield).
      * Nominal DC resistance (each conductor): 24.0 ohms per 1000 feet.

      * Nominal DC resistance (shield): 2.35 ohms per 1000 feet.
      * Shield type: Overall braided with drain wire.
      * Approval: Underwriters Laboratories (UL).


      DTE Data Rate [kb/s]
     Maximum DTE Cable Lengths [ft]

      RS232C
     V.35
     RS449/422
     RS530/422

      56 or 64
     10
     4000
     4000
     4000

      224 or 256
     N/A
     3500
     1700
     1700

      896 or 1024
     N/A
     1700
     350
     350

      N/A - not aplicable (these rates cannot be used for RS232C interface



NOTE on RS-232 Serial Cables

At lower peripheral speeds of up to 9600 baud,serial interfaces can usually
operate over cables up to 50 feet long. Use of special high quality cable
may in some cases allow this limit to be extended to as much as 150 feet.


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