DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si
555-230-127 Issue 1
August 1997
Maintenance Architecture
Page1-17Service 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 E RL 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 termin al 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
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