Patton electronic 2720/I Series NI Status, Valid Interval Count & Current Interval Time

NI STATUS

The Network interface (NI) status is shown in the middle of the Diagnostics/Statistics screen. The brackets are empty when the link is operat- ing normally. In this example, various two or three-letter messages are displayed within the brackets, illustrating what you may see if the Model 2720 is not connected at all or is in a loss of signal condition. Here are the eight status mes- sages.

Excessive zeros [EXZ], i.e., lack of pulses, detected. This condition may occur if the unit is not connected to the network, in which case the EXZ is displayed continuously. If EXZ comes on intermittently, there may be a frame, line code or data rate mismatch between the near and far-end units.

Receiver Carrier Loss [RCL] occurs when 192 consecutive zeros have been detected at the network interface. RCL clears when a pulse is detected.

Frame Bit Error [FE] occurs when there is an error in the framing bit sequence. This may happen due to a disconnected line, mismatched framing formats or severe errors in the data stream. This error may indicate a noisy line or cable condition. This error may indicate a noisy line or cable connection if the frames appear to be set correctly.

Severe Frame Error [SE] occurs when the framing error exceeds a certain threshold of errors. This may happen due to a disconnected line, an extremely noisy connection, or mismatched framing.

Loss of Sync [LOS] occurs when the T1 framer in the unit cannot synchronize itself to the received data stream. This may happen due to a disconnected line.

Out of Frame [OOF] occurs when no valid frame structure can be found. This may happen due to a disconnected line or mismatched framing or mismatched framing.

Alarm Indication Signal [AIS] indicates that the remote unit or the central office is sending a Blue Alarm, because it is not receiving a sig- nal; the alarm is an unframed all-ones signal, mainly used to keep the line alive and to indicate that it is not receiving any signal. This may indicate that the local unit is receiving a good signal, but that the trans- mit link may be broken.

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Receive Alarm Indication [RAI] indicates that the local unit is receiv- ing a Yellow Alarm. This alarm is sent by the remote unit or the central office when it loses the received signal. This indicates the local unitÕs transmitted signal is not reaching the remote unit.

Rx Level The Model 2720 displays the current received signal strength in dB. There are four level ranges detected:

+2 to Ð7.5 -7.5 to Ð15 -15 to Ð22.5 < -22.5

Valid Interval Count & Current Interval Time

The Valid Interval Count and Current Interval Time display the number of valid 15 minute intervals in the last 24 hours and the num- ber of seconds which have elapsed in the current interval, respectively. The Valid Interval Count saturates at the count of 96 (96 * 15min = 24 hours), while the Current Interval Time rolls over after 900 counts. When the counter rolls over, it is reset to zero, and the Interval Counter is incremented by one if the count is less than 96.

Valid Interval Count: [96]

Current Interval Time: [899]

Error Counters

These error counters give a second-by-second snapshot of the link performance. To clear all counters, press the [Backspace] key. If your keyboard does not have this key, you can press a two-key combi- nation to affect the same result: Hold down the [Ctrl] key and then press the [H] key. This will send to the unit the Ctrl-H character, which is the same as pressing the [Backspace] key.

ERR SEC:	0	0	Errored Seconds in Current Interval....
UAS SEC:	557	209	Unavailable Seconds
SE SEC:	0	0	Severely Errored Seconds
BE SEC:	0	0	Bursty Errored Seconds
LOF SEC:	0	0	Loss of Frame Error Seconds

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