WARNING when asterisk*CLI>dahdi restart

我使用 A1200P + 4FXO，装的是dahdi驱动。
当我在asterisk 中执行 dahdi restart 时，总是会出现warning

请问技术支持同学：为什么会这样？是不是哪里配置不正确？如何消除warning？

谢谢！

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asterisk*CLI>
asterisk*CLI>
asterisk*CLI>
asterisk*CLI>
asterisk*CLI> dahdi restart
Destroying channels and reloading DAHDI configuration.
Initial softhangup of all DAHDI channels complete.
Final softhangup of all DAHDI channels complete.
== Unregistered channel -2
== Unregistered channel 1
== Unregistered channel 2
== Unregistered channel 3
== Unregistered channel 4
== Parsing '/etc/asterisk/chan_dahdi.conf': Found
== Parsing '/etc/asterisk/dahdi-channels.conf': Found
[Apr 2 18:34:53] WARNING[3401]: chan_dahdi.c:4101 handle_alarms: Detected alarm on channel 1: Red Alarm
-- Reconfigured channel 1, FXS Kewlstart signalling
[Apr 2 18:34:53] WARNING[3401]: chan_dahdi.c:4101 handle_alarms: Detected alarm on channel 2: Red Alarm
-- Reconfigured channel 2, FXS Kewlstart signalling
[Apr 2 18:34:53] WARNING[3401]: chan_dahdi.c:4101 handle_alarms: Detected alarm on channel 3: Red Alarm
-- Reconfigured channel 3, FXS Kewlstart signalling
[Apr 2 18:34:53] WARNING[3401]: chan_dahdi.c:4101 handle_alarms: Detected alarm on channel 4: Red Alarm
-- Reconfigured channel 4, FXS Kewlstart signalling
-- Automatically generated pseudo channel
== Parsing '/etc/asterisk/users.conf': Found
asterisk*CLI>
asterisk*CLI>
asterisk*CLI>

问题解决了……
这里产生的warning是在提示FXO模块没有插电话线。
插上电话线，warning消失