AFCC Technical Report. Use of Short Range Modems (SRM).
Abstract
New economical Short-Range Modems (SRM) take advantage of the fact that metallic wire transmission paths are not constrained by 3-4 KHz filters as is common in the FDM/TDM voice channel hierarchy. They are capable of handling higher bit rates (50 KB/s is common) at considerably less cost than the more complex 4 KHz limited voice channel modem. The problem encountered in engineering a data transmission path using SRMs is, that unlike the voice channel and the voice channel modem, no standards exist for either the metallic wire path or the SRM. Most SRM vendors specify a maximum bit rate over a maximum wire path length of some specific wire size (with no externally induced noise). Of course, such paths do not exist in the typical Air Force Wire Plant where mixed size, age, and cable type will be found in a given path. This report provides methods for modeling wire paths (theoretically, in the laboratory and in the field) and methods to assess the estimated performance of the various types (modulation/demodulation) of SRM designs over these paths. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1981
- Accession Number
- ADA105597
Entities
People
- J. Su
- L. Rousseau
- T. H. Weaver Jr
Organizations
- Computer Sciences Corporation