I noticed this comment in the Vm1.pdf on the Asterisk Documentation Project:
If you have purchased an Asterisk developer kit from Digium, you will be able to connect your system directly to the Public Telephone Network, as well as run an analog phone from it. If you do not have a development kit, you will be restricted to using IP trunking and clients.
I think the way it was explained in the docs you read, it reffers to being able to connect to PSTN, not the licencing of it. With Digium card included in the dev kit you will BE ABLE to connect to PSTN as well as run analog phone from it, whereas without it (like if you use X100P card) you won’t BE ABLE to run analog phone from it. I saw no mention of Digium licencing on hooking up on PSTN…
Since you got the hardware, the other thing you need is the book “Asterisk, the future of telephony” in order to learn some more about *, but I would assume you already did that…
You bought the hardware now, does it work? I think there’s no need of licencing or anything like that…