In T1 and E1 mode the primary rate interface can work with totaly different framing types on layer 1. The framing type must match the configuration of the first connected point e.g. the exchange or the NT e1(1) E1 - minimum mode, CCITT Recommendation G.704 (Table 4a) e1-crc(2) E1 , crc mode, CCITT Recommendation G.704 (Table 4b) e1-mf(3) E1 , CCITT Recommendation G.704 (Table 4a) with Timeslot 16 multiframing enabled e1-mf-crc(4) E1 , CCITT Recommendation G.704 (Table 4b) with Timeslot 16 multiframing enabled t1-esf(5) T1 , Extended SuperFrame mode DS1 t1-d4(6) T1 , AT&T D4 format DS1 t1-framings can only be set when pmxIfLayer1Mode is t1 e1-framings can only be set when pmxIfLayer1Mode is e1 The default framing for t1 is t1-esf, the default framing for e1 is e1-crc Modifications of the default values are usualy not required. Exceptions are only known for sweden and france (use e1)