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 b y termination and/or loop inp ut impedances. The system
provides an acc eptable level of echo p erformance if the ERL and SFRL are met.

Peak Noise Level

■Analog to analog — 20 dBr nC (decibels ab ove reference noise with
C-filter)
■Analog to digital — 19 d BrnC
■Digital to analog — 13 dBrnC

Echo Path Delay

■Analog port to analog port — < 3 ms
■Digital interface por t to digital interface port — < 2 ms
Service Codes
Service codes (for the United States only) are issued by the Federal
Communications Commission (FCC) to equipmen t manufacturers and
registrants. These codes denot e the type of registered terminal eq uipment and
the protective charac teristics of the premises wiring of the terminal equipment
ports.
Private line service codes are as follows:
■7.0Y — Totally protected private communications (mi crowave) systems
■7.0Z — Partially protected private c ommunications (microwave) systems
■8.0X — Port for ancillary equipment
■9.0F — Fully protected terminal equip ment
■9.0P — Partially protected terminal equi pment
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 tr unk connection ERL should meet or exceed 27 d B SFRL
should meet or exceed 20 dB