This variable indicates the variety of DS1 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: dsx1ESF Extended SuperFrame DS1 (T1.107) dsx1D4 AT&T D4 format DS1 (T1.107) dsx1E1 ITU-T G.704, (Table 5A) dsx1E1-CRC ITU-T G.704, (Table 5B) dsxE1-MF G.704 (Table 5A) with TS16 multiframing enabled dsx1E1-CRC-MF G.704 (Table 5B) with TS16 multiframing enabled dsx1Unframed DS1 with No Framing dsx1E1Unframed E1 with No Framing (G.703) dsx1DS2M12 DS2 frame format (T1.107) dsx1E2 E2 frame format (G.704) dsx1E1Q50 TS16 bits 5,7,8 set to 101, [in all other cases it is set to 111.] (G.704, table 14) dsx1E1Q50CRC E1Q50 with CRC dsx1J1ESF J1 according to (JT-G704, JT-G706, and JT-I431) dsx1J1Unframed J1 with No Framing

For clarification, the capacity for each E1 type is as listed below: dsx1E1Unframed - E1, no framing = 32 x 64k = 2048k dsx1E1 or dsx1E1CRC - E1, with framing, no signalling = 31 x 64k = 1984k dsx1E1MF or dsx1E1CRCMF - E1, with framing, signalling = 30 x 64k = 1920k