Accession Number : ADA105597

Title :   AFCC Technical Report. Use of Short Range Modems (SRM).

Descriptive Note : Final rept.,

Corporate Author : COMPUTER SCIENCES CORP FALLS CHURCH VA

Personal Author(s) : Rousseau,L. ; Su,J. ; Weaver,T. H. , Jr

Report Date : 01 SEP 1981

Pagination or Media Count : 426

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)

Descriptors :   *Modems, *Data rate, *High rate, Specifications, Military applications, Air Force operations, Cables, Noise(Electrical and electromagnetic), Short range(Distance), Data transmission systems, Data links, Wire, Length, Digital systems, Modulation, Demodulation, Drives(Electronics), Signal to noise ratio, Crosstalk

Subject Categories : Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE