[Asterisk-Users] How to prevent FXO transfers

[Soner Tari]

Hi,

I use Grandstream HT486 with Asterisk. I dial 9 to get an FXO line, then 
hangup and wait 1-2 secs. Then, I dial immediately 9 again to get another 
outbound channel and hangup again. Guess what happens, the two outbound 
lines are connected indefinetly.

The cause of this issue is that I guess since HT486 senses hangups too 
slowly, when I hold the handset again it assumes a hook-switch, thus 
Asterisk thinks that the user will transfer the channel, thus puts a 
musiconhold, etc. I've set the Send Flash Event to Yes, and it solves this 
problem, but now the users cannot transfer using hook-switch. I want 
hook-switch on HT486. (I have *8 for transfers of course, but most users are 
more familiar with hook-switch, and instructing users to slow down is not 
nice.)

The better solution would be of course to prevent 2 outside lines to be tied 
together. I mean, one should not be able to transfer an FXO line to another 
FXO line (this is necessary even if HT486 was not responsible for this 
issue). I could not find such a setting in Asterisk. How do I do that? 
Perhaps I could do it in extensions.conf, any idea?

Thanks,
Soner