This attribute indicates the E.164 address which is expected in the
trail access point identifier, which is transmitted using the Trail
Trace (TR) field of the transmitted E3 Frame.
Both the expected trail access point identifier and the transmitted
trail access point identifier are provisionable attributes of the G832
component.
The 16 byte Trail Trace frame is composed of one byte containing a
frame start marker and a CRC-7 calculation over the previous
frame, and 15 bytes for transporting an E.164 address. If less than
the full 15 bytes are used, the address is padded with NULL
characters.