Tips for implementing a testing lab

[WhiteTiger-IT]

I need to implement a testing lab and would like some advice.
At the moment I can use VMWare Workstation 17.5 or Proxmox (yet to be installed).
I can also use a Raspberry 4B.
I also have a FritzBox 7530AX running OS 7.57, connected to the Internet and with an assigned phone number.
Finally I have a FritzFon.

In my intentions the laboratory should receive telephony through the FritzBox to forward them to FritzFon and to Xubuntu and Windows VMs.
I was thinking of activating at least 30 VMs to test at least 20 In/Out calls, 10 from outside and 10 between internal numbers.

In addition to some advice, I would like to know:

1. Is there already a VM that I can activate without having to worry about installing and configuring Asterisk?
2. Are there any virtual phones you can use, in Linux or Windows?
3. Can VoIP numbers be activated without costs? Since they are for testing, the presence of limitations is obviously acceptable.

Thanks in advance

[penguinpbx]

@WhiteTiger-IT

Is there already a VM that I can activate without having to worry about installing and configuring Asterisk?

Asterisk is a toolkit; if you want a VM/distro, then you might try FreePBX.

As for doing it on a VM vs. standalone hardware, well, any computer built in the last ten or so years can handle this software and will probably not require quite as much firewall/port/IP address configuration.

@WhiteTiger-IT

Are there any virtual phones you can use, in Linux or Windows?

Linphone comes to mind first today.

And you might find a few cheap physical SIP desk phones are worth a test.

@WhiteTiger-IT

Can VoIP numbers be activated without costs? Since they are for testing, the presence of limitations is obviously acceptable.

Probably not. But a SIP trunk budget of a few bucks per month can still go pretty far these days.