2-4 DS-1 configuration
297-2521-106 Standard 23.01 March 2001
— BPV is an indication of a coding error in the received bit stream.
BPV indicates local span performance.
— CRC, applicable only with extended superframe format (ESF), is an
indication of one or more bit errors in a block of bits from the
received bit stream. CRC indicates performance on an end-to-end
span.
• Channel framing identifies the location of time slot one. The signaling
frame identifies those frames in which two signaling states, A and B, are
transmitted on a time-shared basis. Table 2-2 shows the assignment of
the F-bit, A-bit, and B-bit; the most significant bit is defined as bit one
and the least significant bit as bit eight.
Table 2-2
Superframe format bit assignments
Frame
number
F-bit
terminal
framing
F-bit
signaling
framing
PCM
coding
bits
Signaling
bit
Signal
channel
1 1 1–8
2 0 1–8
3 0 1–8
4 0 1–8
5 1 1–8
6 1 1–7 8 A
7 0 1–8
8 1 1–8
9 1 1–8
10 1 1–8
11 0 1–8
12 0 1–8 8 8
—end—
• The superframe format is consistent with channel bank formats D2, D3,
and D4. The signaling bit is time-shared to identify the channel and the
signaling frame. The framing pattern is the repeated sequence
100011011100. The superframe format is supported on both types of
DS-1 cards (6X50AA and 6X50AB).
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