13
14
B8ZS:
This stands for "Bipolar 8 Zero Substitution." This line code
ensures minimum ones density. Long sequences of zeros are
specially encoded. This line code allows any data pattern to
be transmiited without causing ones density problems. Thus,
it allows the use of 64 kbps timeslots.
SW2.4
Line Code
Off
B8ZS
On
AMI
Switch SW2.3: Line Framing
This switch is used to set the frame. There are three framing
modes available in the Model 2710A Series: ESF, D4 and Unframed.
When SW1.8~SW1.4 are turned off, the unit is set to unframed opera-
tion, and SW2.3 is ignored. Otherwise, SW2.3 is used to set the frame
to either ESF or D4.
SW2.3
Frame
Off
ESF
On
D4
Line Framing Options
D4/Superframe: The D4 framing format, as specified in AT&T TR62411
is the standard in which twelve frames make up a superframe. All sig-
naling and synchronization is done in-band.
Extended Superframe: Extended Superframe, as specified in AT&T TR
54016, consists of twenty-four (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 2710A and the Central Office.
Switch SW2.2: DS0 Channel Rate
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.
SW2.2
DS0 Rate
Off
56 kbps
On
64 kbps
Switch SW2.1: Clock Mode
This switch is used to select the timing source for transmitting data
to the network. External clocking is available only in unframed mode
(DTE data rate of 1544 kbps).
NOTE: When using the Model 2710A to terminate the telephone
company's T1 service, the 2710A must be set to network
clock. When using the Model 2710A as a high-speed short
range modem, one unit of the link must be configured for
Internal Clock mode, and the unit on the opposite end must
be configured for Network Clock mode.
Function
SW2.2
SW2.1
Clock Mode
Don’t Care
Off
Network
Don’t Care
On
Internal
Don’t Care
Off
Network
Off
On
Internal
On
On
External
CLOCK MODE
Framed Mode (ESF/D4)
Unframed Mode
Note:
1. For unframed mode (1544 kbps), set SW1.8,
SW1.7, SW1.6, SW1.5 & SW1.4 to OFF.
2. In unframed mode, SW2.3 is ignored.