MAINTENANCE ACCESS LINES
1 General
1.1 Introduction
1.2 Quiet termination test line
1.3 Test and/or communications access line
1.4 Echo suppressor test line
1.5 Loopback test line
1.6 Echo canceller test line
1.7 ATME No. 2 test lines
1.8 Busy flash signal test line
2 Method of access
3 Specifications for the test line apparatus
3.1 Tone source characteristics (quiet termination and loopback test lines)
3.2 Transmitted level and timing intervals (quiet termination and loopback test lines)
3.3 Impedance
3.4 Return loss
3.5 Frequency response
3.6 Loopback test line level adjustment
3.7 Digital loopback test
4 Signalling system test line test sequence
4.1 Circuit seizure
4.2 Test line answer
4.3 Test line not equipped