HP AD278A and AD279A PCI Multiplexer Support Guide, November 2008

NOTE: Not all RoHS products support all of the data rates listed below.
Table A-4 Data Rate Versus Cable Length
Maximum Cable LengthData Rate (bps)
100 feet (3048.000 cm)57,600 or less
80 feet (2438.400 cm)115,200
40 feet (1219.200 cm)230,400
20 feet (609.600 cm)460,800
10 feet (304.800 cm)921,600
The maximum length is the length of the cable from the adapter that is connected to a HP supplied
interconnect device, such as a fan-out cable.
The maximum length is based on a cable rated at:
• 12.3 pF/foot, conductor to conductor
• 22.4 pF/foot, conductor to shield
If low-capacitance cable is unavailable or very long cable runs are required, short-haul modems
can be used to increase the effective range of the RS-232 interface. Short-haul modems are similar
to standard modems, except that they are connected directly to each other through a cable instead
of a telephone circuit.
Use only externally-powered short-haul modems with the RoHS adapters.
Transmission Errors
If transmission errors occur, perform one of the following tasks:
• Reduce the baud rate.
• Reduce the cable length.
• Use a cable with a lower capacitance per foor rating.
32 Technical Specifications