User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 2-13
Product Description
Framing Modes
DL
t
Bits
The three C-bits in Subframe 5, called the DL
t
bits, are assigned as a 28.2-Kbit/s terminal-to-
terminal path maintenance data link. This link uses a link access procedure on the D-channel
(LAPD) to transmit the DS3 path identification number, DS3 idle signal identification, and DS3
test signal identification. See Figure 2-6.
Figure 2-6 Subframe 5 C-bits
MO
679
Bits
X 679 679 679 679 679 679P P MO M1 MO
M Frame (4760 bits)
Subframe
1
Subframe
2
Subframe
3
Subframe
4
Subframe
5
Subframe
6
Subframe
7
MO 84 F1 84 84 84 84 84 84 DLt FO DLt FO DLt F1 4
680
Bits
M Subframe No. 5
S5 79
Transmit path identification number
over path-maintenance data link in
point-to-point application