TA TSY 000465 : ISSUE 1

The Pair Gain Test Controller (PGTC) was developed and introduced into the local network by AT & T during the 1970's for testing a wire center's locally switched circuits that are served by digital loop carrier (DLC) systems. The PGTC is an embedded testing interface and is documented in TR TSY-000465. The Extended Test Controller (XTC) is an enhancement by AT & T to the PGTC to provide for testing of non-locally switched circuits via SARTS and MLT. This Technical Advisory, Supplement 1 to TR TSY-000465, specifies the electrical, physical, and message interfaces between the XTC and a DLC system