The TX board monitors carrier alarm conditions. If the application requests it, the setting and clearing of these alarm states can be reported as unsolicited status events or can be returned on request with TxT1E1CarrierStatus. The TX board can also report other carrier status changes such as establishment and loss of synchronization and detection or loss of carrier signal.
The following table lists the alarms detected by the TX board:
Alarm state |
Entry criteria |
Typical usage |
Blue alarm (AIS) |
Unframed all ones signal received for 3 ms (T1/J1) or two full frames (E1). |
Far end cannot transmit normal signal (for example, a repeater lost the incoming carrier on the other side). |
Yellow alarm (distant or far end) |
D4: Bit 2 in every channel set to 0 for ~ 335 ms. ESF: 16 consecutive patterns of 0x00FF appear in the facility data link (FDL). E1: Bit 3 of timeslot 0 in non-align frames set to 1 for three consecutive occasions. |
Far end lost incoming signal from reporting node. |
Timeslot 16 alarm indication signal (E1 only) |
E1 CAS mode only: Timeslot 16 contains all 1s for 16 consecutive frames (one full multiframe). |
Far end lost normal CAS signaling capability (for example, lost incoming CAS signal on other side). |
Timeslot 16 signal lost (E1 only) |
E1 CAS mode only: Timeslot 16 contains all 0s for 16 consecutive frames (one full multiframe). |
Failure of equipment providing CAS signaling. |
Distant multiframe alarm (E1 only) |
E1 CAS mode only: Bit 6 of timeslot 16 of frame 0 set to 1 for two consecutive multiframes. |
Far end lost CAS multiframe alignment. |