HP AD278A and AD279A PCI Multiplexer Support Guide (Edition 1), September 2006

Technical Specifications
Cable Requirements and Specifications
Appendix A
41
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 task:
• Reduce the baud rate.
• Reduce the cable length.
• Use a cable with a lower capacitance per foor rating.