Is there a limitation to how many DNs you can associate with one phone in FreePBX?

I’m trying to deploy a DECT IP network using Cisco Unified Communications Manager (CUCM).
“CUCM” is essentially just a Cisco PBX and “DECT” is just a protocol for handsets to communicate with base stations.

I think I found a limitation in CUCM.
Basically, when you register a phone using “Third-party SIP (Basic)” template in CUCM - you can associate 1 DN with 1 phone.
However, if you register a phone using “Third-party SIP (Advanced)” template in CUCM - you can associate 8 DNs with 1 phone.

As for how the DECT IP works - you have a PBX, you register a base station (phone) to the PBX and then you can register multiple wireless handsets to the base station. People carry the wireless handsets around and as long as they’re in base station range - they are able to make and receive calls. Each handset has a DN associated with it.

The problem is that the base station model we have allows for up to 30 handsets to be registered to it. However, I can only associate 8 DNs in CUCM with one phone (base station).

And now I wonder… Is there a limitation to how many DNs you can associate with one phone in FreePBX?

DECT system make/model?

If it can be configured to register each handset separately (from different source ports and/or IP addresses), you can set up 30 extensions in FreePBX and it will be fully functional.

If all traffic must go via a single IP/port, you would configure the base as a trunk in FreePBX. For outgoing calls, just set the trunk Context to from-internal; for incoming, set up 30 Custom extensions that dial the trunk. Most common features (voicemail, DND, forwarding, follow-me) should work, but some may not. For example, if you want the handsets to have different outbound calling restrictions, or different languages, you would need to write custom dialplan for that.