Line Code Violations (LCV) are either bipolar violations or excessive zero
violations.
Path Code Violations (PCV) are either frame bit errors in the case of SF (D4)
framing or CRC errors in the case of ESF framing.
The led indicators above the LCD are there to show you the status of the T1 circuit
at a glance, while the display is used to provide more detailed information. The
exact meaning of a particular led being lit can be summarized as follows:
Carrier Detect
means that a T1 clock has been detected on the receive pair.
Framing
means that the received T1 carrier is framed (either SF or ESF).
Data Detect
means that the data within the received frames is neither all ones nor
all zeros. In other words, it indicates the presence of payload data inside the
framed carrier.
Alarm
means that one of the following conditions exists.
- LOS (loss of signal) simply means that the D630 is not receiving any T1 carrier.
This is one of the conditions referred to as a Red Alarm.
- AIS (Blue Alarm) means that unframed ones are being received. In general, this
means that the upstream device is looped up or is off line.
- RAI (Yellow Alarm) will be received by the D630 if the telco does not see the T1
carrier sent from the D630. It’s not unusual to see this when you first connect.
Looped Up
means that the D630 received (and responded to) a CSU loop-up code
from the telco and will remain looped until (a) it receives the loop-down code or
(b) an LOS condition occurs or (c) an AIS alarm is received.
Error
simply means that the LCV count and / or the PCV count is non-zero. These
counters are cleared each time the D630 goes out of frame or is unplugged.
NOTE:
The T-Spanner automatically determines the line coding by detecting the
B8ZS code words in the received data. If insufficient consecutive zeros are
present to cause a B8ZS code word substitution, then the line coding cannot be
determined. In this case, the T-Spanner will assume AMI line coding for SF (D4)
framing and B8ZS line coding for ESF framing.
NOTE:
The D630’s audible alert uses the following scheme to call your attention to
any alarm or fault condition, a status change or a new LCD message.
1 beep = mode change or new LCD message is up
2 beeps = any power related event
3 beeps = T1 fault or error message
4 beeps = D630 fault or error, such as a POST failure
NOTE:
If the D630 is turned on but is not connected, it will go into a “low power”
mode and will eventually shut itself off, in order to conserve battery life. When
the 630 is connected to a network, then it will stay on and continue testing
indefinitely until it is manually switched off or until it is disconnected.
