Simultaneous calls with new broadband connection

Hi everyone, I have really little knowledge about telephony/VoIP Server, so here I am asking you.

There is this company with a Patton, FreePBX and an ISDN connection. They have it all setup to work like that (they are pushing this work onto me, the one who did it just left), and now the ISP has suggested them a new contract with a broadband connection. Is it possible to configure FreePBX as VoIP Server with that connection and still do simultaneous calls? In that case there is just to remove the Patton and fix the configuration of the FreePBX, right?

Please ask if you need more information, thank you all.

Yes its possible

sounds like the Patton is the current PSTN gateway /// freepbx would stay in place and youd configure a new PSTN trunk and adjust inbound/outbound routes as needed

Thank you for your reply.

When you say PSTN trunk do you mean a Sip trunk in FreePBX?
Now I’m trying to simulate their situation with a VM and FreePBX in office with our ISP (we have a broadband), asked SIP Key and Outbound Proxy at my ISP, I set it all up (with a Sip trunk) but it seems there is something wrong. I can do outbound calls, can receive inbound calls, but sometimes when someone calls it just says “the number called doesn’t exist” even though the number called is correct. I tried anyway to do simultaneous calls (first outbound call with our telephone and second call with Zoiper in a PC) but the second call says “already busy” so it doesn’t work…

I’d like to replicate their situation before going to say “all good” to them so here I am.