PHP AGI Problem with serial communication

[wlady]

Hello,

I wrote an AGI PHP script for an elastix 2.0.0 PBX that uses a php class to communicate with a serial port (for domotic applications).

I use this class: http://www.phpclasses.org/package/3679- ... -port.html

The script works perfectly if launched from linux terminal thru PHP command, but not from asterisk exten.

I've enabled AGI debug and it only returns a : AGI Tx >> 510 Invalid or unknown command
In PHP log file I see an "invalid port" error, but I'm sure port is correct

Any suggestion?
Thanks!