DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Maintenance Architecture
1-42Service Codes
1
ERL and SFRL Talking State
Echo-Return Loss (ERL) and Single-Frequency Return Loss (SFRL) performance
is usually dominated by termination and/or loop input impedances. The system
provides an acceptable level of echo performance if the ERL and SFRL are met.
Peak Noise Level
■ Analog to analog — 20 dBrnC (decibels above reference noise with
C-filter)
■ Analog to digital — 19 dBrnC
■ Digital to analog — 13 dBrnC
Echo Path Delay
■ Analog port to analog port — < 3 ms
■ Digital interface port to digital interface port — < 2 ms
Service Codes
Service codes (for the United States only) are issued by the Federal
Communications Commission (FCC) to equipment manufacturers and
registrants. These codes denote the type of registered terminal equipment and
the protective characteristics of the premises wiring of the terminal equipment
ports.
Private line service codes are as follows:
■ 7.0Y — Totally protected private communications (microwave) systems
■ 7.0Z — Partially protected private communications (microwave) systems
■ 8.0X — Port for ancillary equipment
■ 9.0F — Fully protected terminal equipment
■ 9.0P — Partially protected terminal equipment
Station-to-station ERL should meet or exceed 18 dB SFRL
should meet or exceed 12 dB
Station to 4-wire trunk connection ERL should meet or exceed 24 dB SFRL
should meet or exceed 14 dB
Station to 2-wire trunk connection ERL should meet or exceed 18 dB SFRL
should meet or exceed 12 dB
4-wire to 4-wire trunk connection ERL should meet or exceed 27 dB SFRL
should meet or exceed 20 dB
