Each DTI is equipped with an internal channel service unit (CSU). When enabled, the internal CSU monitors the quality of the received T1 signal and provides performance statistics and diagnostic information.
DTIs must be individually programmed to establish parameters for collecting and measuring transmission performance statistics by the CSU.
Statistics Installer password required
The CSU provides both performance and alarm statistics. Three performance parameters are accumulated:
• errored seconds (ES-P)
• severely errored seconds (SES-P)
• unavailable seconds (UAS-P)
These parameters are defined as per TIA-547A. Errored seconds are enhanced to include control slip (CS) events.
The parameters are stored for the previous 15-minute interval, the 15-minute intervals in the last 24 hours, and the previous 24-hour interval. Only near-end performance data is recorded.
The internal CSU continuously monitors the received signal and detects four types of transmission defects:
• any active carrier failure alarms (CFA) — loss of signal LOS, out of frame OOF, alarm indication signal AIS, remote alarm indication RAI
• the number of bipolar violations that occurred in the last minute