User guide

August 2001 107
Configuring the E1 Environment
Configuring the Hook State
When loaded, each protocol automatically transmits the bit
pattern corresponding to the idle state. The devices ignore the
‘Hook’ field in the carrier parameters.
Transmitting the proper hook state is one reason to load the
protocols before configuring the carrier parameters. If you
configure the carrier first, the board might transmit an invalid
hook pattern on the line. This invalid signal could trigger
alarms at the CO. Although the alarms would disappear when
you load the line protocol and begin transmitting the
appropriate bit pattern, the CO switch might have blocked the
line in response to the alarm.
Configuring ADI
Alternate Digit Inversion (ADI) consists of analyzing the data
transmitted in each channel and making sure it does not go
beyond certain amplitude limit. If it does, the signal is
automatically modified so that it remains inside a
pre-determined range. For audio data, ADI should always be
enabled.