Patton electronics 2720/I Series User Manual page 22

Remote In-band Loops: Enabled (default)
Options: Enabled, Disabled
In ESF, D4 and Unframed formats, the unit can respond to special
repeating codes in the data stream that represent loopback com-
mands. The command to loop up (go into loopback) is a repeating pat-
tern of 00001s. This pattern overwrites the normal data. When this
code is detected for 5 seconds, the unit will go into loopback if the
Remote In-band Loopback is Enabled. When a repeating code of 001s
is received for 5 seconds, the unit loops down (goes out of loopback).
The delayed recognition guards against false starts, since the code
must be present for a long time continuously. When Disabled, the unit
will recognize the codes but will not respond to them. The loopback
timeout also applies to this feature.
V.54 Loops (RDL Only): Enabled (default)
Options: Enabled, Disabled
This is a special in-band loopback facility that sends a special
pseudo-random pattern over the data stream. This is the only remote
loopback that the unit can initiate. This is useful for campus applica-
tions when you need to put a remote unit in loopback. The remote unit
responds to the V.54 loopback command, and the whole process takes
only a few seconds to complete. This setting will enable/disable RDL
from being initiated from either the control port or the DTE interface. It
will also enable/disable the unit to respond to the V.54 command if
received over the line. The duration of the loopback is limited by the
loopback timeout setting. (See Unit Operations, paragraph 3.2.4, on
pages 32 and 33.)
Default Config Source: Switch (default)
Option: EEPROM, Switch
The Model 2720 can be initialized via the configuration in the on-
board permanent memory (EEPROM) or via the internal DIP switches
(Switch). Once the unit is powered up, you may change the settings
through the control port or the DIP switches.
If you do not have a terminal, you may force the unit to use the
DIP switches as the default configuration source by turning off the unit,
setting all the DIP switches to the ON position, then powering on the
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