Patton electronic Model 2711 User Manual

Page 10

ALM

(Alarm) glows red to indicate that one of
several alarm conditions exist. These con-
ditions may be local alarms or remote alarm
conditions. Alarms may occur due to:

•

Loss of Synchronization

• Loss of Frame

• AIS (Blue Alarm)

• Yellow Alarm

ERR

(Error) flashes to indicate errors. There are

several flashing patterns to indicate the type

of error.

Invalid Switch Configuration: It is possible

to request more bandwidth than is possible.

For instance, if you set the starting channel

to 12, and you select a number of timeslots

exceeding 13, the unit will not be able to

satisfy your request. In that case, the ERR

LED will flash once a second (fi second on,

fi second off). When the unit detects an

invalid setting, it will ignore the setting and

default to a full T1 (bandwidth = 24 chan-

nels, starting channel = 1). This will contin-

ue until you set the switches to a valid set-

ting. The invalid switch configuration condi-

tion overrides other error conditions. Thus, if

• Errored Second: In ESF or SF framing, if

the unit detects a frame error, the ERR LED

will flash briefly once a second.

• Framing Mismatch: the ERR LED flashes

briefly once a second when framing modes

are mismatched.

• Loss of Signal: When there is no signal

at the network interface, the ERR LED will

flash briefly once a second.

TST

(Test/Loop) glows yellow to indicate that the

unit is in a test mode. The unit may be in

any one of the following modes:

• D4 Line Loop (CO initiated)
• ESF Line Loop (CO Initiated)

• ESF Payload Loop (CO Initiated)

PWR

(Power) glows green to indicate that the unit

is receiving power.

5.2 CENTRAL OFFICE LOOPS

The 2711 also responds to central office initiated loop commands.

When in D4 framing mode, the 2711 will implement the “loop up” com-
mand when it recognizes the pattern “10000” in the data stream for a
minimum of 5 seconds. The “loop down” command is implemented by
the pattern “100” in the data stream for a minimum of 5 seconds.

When operating in ESF framing mode, loopback commands are

issued via the Facility Data Link (FDL). The line loop message will
cause a loop back before data enters the framer portion of the CSU.
The payload loop message will cause the 2711 to loop data after the
framer portion of the CSU.

The 2711 will respond to Universal Loopback Deactivate to clear

all central office loops.