I have a issue with my SCCP Phones SPA502G, the call between the Pantel VoIP and IP Phones can be completed. But the function to open the door by pressing one digit, for example, 8 cant work it.
Ive checked and maybe it was a bug of Pantel and the DTMF relay not worj between SCCP and SIP Pantel.
Ive checking about change the firmware of SPA502G but ive read that for UC540 doesnt support SIP only SPCP. Someone know some method or if it possible change to SIP?