I have an Asterisk pbx with version 1.4 and running on Centos 5.5. I have a 4 port OpenVox B400E ISDN card on the box. Of late people have been complaining of a beeping tone on some of the extensions when they are making outgoing calls. I swapped out the ISDN card and the issue was resolved but it seems as if it was short leaved as it has started again. I have plugged an analogue phone on the lines but do not hear the beeping tone but only get it when making outgoing calls in the Asterisk box.
Has anyone experienced this and point me in the right direction