The BERT measurement Event List updates errors, signal loss, frame loss, and alarms every second. Alarms are: AIS ON, AIS OFF, RAI ON, and RAI OFF. The data is displayed as a log list. The display will list up to 1000 errored seconds.
Rx Signal Measurement Procedure
1. Press the Measurements main menu key to activate the Measurements menu.
2. Press the Rx Signal submenu key to activate the Rx Signal menu.
The VF Channel Access test feature enables testing on each of the 1 to 24 DS1 64kb DS0 channels from one of the 28 T1 sub‑channels on the T3 signal. The receive channel is decoded, and the VF level and frequency are measured and displayed. The signal is also connected to a speaker, enabling you to make an audible assessment of the signal quality of the circuit. If the circuit is out-of-service, then you can insert a test tone on the transmit channel for measurement at a remote location with another test set, or locally with a loopback.
Configuration
Before conducting channel tests, the T3 interface must be properly configured. Press the Configuration main menu key to display the Signal Setup and Payload Setup windows. Select the correct Framing Mode, Line Coding, and Clock Source. Set the cursor on Payload Type and press the 1.544Mb submenu key.
Note
The receive mode must be set up before connecting to the circuit in order to avoid creating a “hit” on the customer data.
Channel Tests
After the unit is correctly configured, select the VF Channel Access menu to perform tests at the DS0 channel level. Press the Channel submenu key to select specific channels. Either enter a specific channel number from the keypad or scroll through the channels with the Up/Down arrow keys. The received VF level and frequency on the selected channel are displayed, and the decoded signal is connected to a speaker for audio monitoring. When a test tone is present on the channel, the level and frequency report indicate whether the channel is healthy. If speech is present on the channel, then the channel performance can be judged from the audio quality. An overview of channel utilization can be obtained by quickly scrolling through the channels.
If the circuit is out-of-service, then you can connect to the transmit pair and insert a test tone on the selected channel (note that transmit and receive must be on the same channel). Two menus enable selection of transmit level and frequency. The frequency can be entered from the keypad, or scrolled to common test frequencies (404 Hz, 1004 Hz, 1804 Hz, and 2713 Hz) with the Up/Down arrow keys. To check the performance of channel level equipment, the test tone can be measured at a remote location with another VF channel test set.