Alcatel 060170-10, User Manual, Page: 179 / 430

VoIP Commands
Page 5-37
Remarks
The
voice port frame format
command is used to indicate the type of DSL line implementing the
circuit. The 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 time slot divisions, which are the basis for T1 and E1 circuit connections, e.g., multi-
plexed Digital Service (DS-1), are determined as follows for frames, superframes, extended
superframes and multiframes.
T1 Framing
A T1 frame consists of 24, 8-bit time slots and a 1 bit-synchronization and control bit.
Twelve (12) T1 frames can be grouped into a superframe (SF/D4), or 24 T1 frames can be
grouped into an extended superframe. In each superframe, the 6th and 12th frame may
contain “robbed bit” (A,B) signaling, which means the least significant bit is robbed from each
time in the 6th and 12th frame and used for signaling. In extended superframes, this robbed
bit signaling (A, B, C, D) occurs in the 6th, 12th, 18th, and 24th frames.
E1 Framing
The E1 frame consists of 32, 8-bit time slots (two of these slots are used for synchronization
and multiframe signaling) for 256 bits per frame at 2.048 megabits per second. Sixteen (16) E1
frames are grouped into multiframe. An E1 multiframe can use Channel Associated Signaling
(CAS) contained in time slot 16. Timeslot 16 in multiframe 0 is used for multiframe synchroni-
zation and control. Timeslot 16 of multiframes 1 through 15 are used to carry A, B, C, and D
signaling bits.