16
MICRO T1 CSU/DSU
S
WITCH
SW2-3 L
INE
F
RAMING
This switch is used to set the frame. There are three framing modes available in the
Micro T1 CSU/DSU: ESF, D4, and Unframed. When SW1-4 through SW1-8 are
turned off, the unit is set to unframed operation, and SW2-3 is ignored. Otherwise,
SW2-3 is used to set the frame to either ESF or D4.
Table 3-7. SW2-3 Line Framing.
SW2-3
Frame
Off
ESF
On
D4
L
INE
-F
RAMING
O
PTIONS
D4/Superframe
: The D4 framing format, as specified in AT&T TR62411, is the
standard in which twelve frames make up a superframe. All signaling and
synchronization is done in-band.
Extended Superframe
: Extended Superframe, as specified in AT&T TR 54016,
consists of 24 T1 frames. The framing bits are now used for framing CRC and the
Facility Data Link (FDL). The FDL allows maintenance messages and information
to be passed between the CSU/DSU and the central office.
S
WITCH
SW2-2 DS0 C
HANNEL
R
ATE
This switch is used to set the DS0 rate in framed modes; in unframed mode, this
switch is used with SW2-1 to set the clocking mode.
Table 3-8. DS0 Channel Rate.
SW2-2
DS0 Rate
Off
56 kbps
On
64 kbps
