This variable indicates the variety of T1/E1 Line implementing this circuit. The type of circuit affects the number of bits per second that the circuit can reasonably carry, as well as the interpretation of the usage and error statistics. The values, in sequence, describe: TITLE: SPECIFICATION: esf Extended SuperFrame DS1 d4 AT&T D4 format DS1 - SF e1 CCITT Recommendation G.704 (Table 4a) - G732N e1Crc CCITT Recommendation G.704 (Table 4b) - G732N with CRC e1MF G.704 (Table 4a) with TS16 multiframing enabled - G732S e1CrcMF G.704 (Table 4b) with TS16 multiframing enabled - G732S with CRC unframed T1 - applicable values: (1),(2),(3),(8) E1 - applicable values: (1),(4),(5),(6),(7),(8)