Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

FXO ports

Hello --

I have a CCME with FXO ports. When should I use the 'no supervisory-disconnect' or ' no battery-reversal' commands as opposed to the defaults.

The literature is a bit sketchy.

Thanks,

Ohamien

1 REPLY
Bronze

Re: FXO ports

When loop-start signaling is used, a router's FXO interface looks like a phone to the switch (private branch exchange (PBX), public switched telephone network (PSTN), Key-System) it connects to. The FXO interface closes the loop to indicate off-hook. The switch always provides a battery so there is no disconnect supervision from the switch side. Since a switch expects a phone user (example of an FXO interface) to hang up the phone when the call is terminated (on either side), it also expects the FXO port on the router to hang-up. This "human intervention" is not built into the router. The FXO port expects the switch to tell it when to hang-up (or remove the battery to indicate on-hook). Because of this, there is no guarantee that a near-end or far-end FXO port disconnects the call once either end of the call hangs-up.

The most common symptoms of this problem are phones that continue to ring when the caller has cleared, or FXO ports that remain busy after the previous call should have been cleared.

For more information kindly follow the url,

http://cisco/en/US/tech/tk652/tk653/technologies_tech_note09186a00800ae2d1.shtml

340
Views
0
Helpful
1
Replies