Patton electronic Model 2711 - Manual (Page 8)

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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 2711 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 2711 and the Central Office.
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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 2711 to terminate the telephone
company's T1 service, the 2711 must be set to network clock.
When using the Model 2711 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 Clocking Mode
Don’t Care Off Network
Don’t Care On Internal
Don’t Care Off Network
Off On Internal
On On External
CLOCKING AND FRAMING MODES
Framed Mode (ESF/D4)
Unframed Mode