Since for each channel only the least significant bit of every six frames is affected,
robbed bit signaling has a negligible effect on the quality of voice transmission.
Figure 1-5. Format of One-Second Reports per ANSI T1.403
Bits
8
7
6
5
4
3
2
1
Word 1
G3
LV
G4
U1
U2
G5
SL
G6
Word 2
FE
SE
LB
G1
R
G2
Nm
N1
G1 = 1
1 CRC Error Event
G2 = 1
2 to 5 CRC Error Events
G3 = 1
6 to 10 CRC Error Events
G4 = 1
11 to 100 CRC Error Events
G5 = 1
101 to 319 CRC Error Events
G6 = 1
320 or more CRC Error Events
FE = 1
At least 1 Framing Bit Error; no SE
SE = 1
At least 1 Severely Errored Framing Event
LV = 1
At least 1 Line Code Violation (BPV)
SL = 1
At least 1slip event
LB = 1
Payload loopback activated
U1, U2
Usage under study
R
Reserved
Nm, N1
Identifies second (previous, previous -1, etc.)
Chapter 1
ACST-0351-005
Introduction
June 1996
1-14