Activate 4 VoIP SIP channels to manage an equal number of simultaneous calls via Urmet-branded ATA FXO gateway devices for interfacing with traditional analogue lines (UTD 1375/864) and ISDN (UTD 1375/872). Licences must be purchased from the portal store.urmet.com and associated with a specific iPerTalk system via the UID identifier that uniquely identifies it.