16 KB/S Modem (AN/GSC-38) CONUS Test
Abstract
A performance test was conducted on the Harris 16 kb/s Modem operating over the CONUS Autovon network. Measurements were made with the modems operating in a full-duplex configuration over four-wire Autovon connections and in a simplex configuration over two-wire Autovon connections. In addition to the 16 kb/s measurements, tests were conducted at 8 kb/s using the 8 kb/s mode of the 16 kb/s modem and at 9.6 kb/s using a commercial modem. In all, 1425 calls were placed in which bit-error-rate (BER) performance was measured. Nine different CONUS subscriber locations were involved. In addition to normal calls between modems located at different subscriber locations, loop-around calls were placed to most of the network switches. The general results indicate that if the access line from the subscriber location is a 'good' one, the 16 kb/s model is capable of providing BER values less than 1% on over 90% of the randomly dialed lines even when an emergency network condition is simulated. The 'good' access lines appear to be those which do not involve N carrier or the early version of T carrier systems (those involving D1A or D1B channel banks). Sixteen kilobit performance over N1 carrier system and T1/D1A or T1/D1B is quite poor and performance over N2 carrier systems is marginal. Performance from two-wire locations appears to be about the same as that from four-wire locations when care is taken to match the modem impedance to reduce reflections.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1980
- Accession Number
- ADB053656
Entities
People
- Daniel D. Mcrae
Organizations
- Harris Corporation