Thanks Iqbal. I got some Digium cards now and I was able to make the asterisk work as a simple pbx. I'll be going to try it out now as a pstn gateway with SER. Though Im not sure if what I have in mind can work. My ser is on the public domain (that is it has a public ip) and my asterisk/pstsn gateway is inside the nat network. From the experience of users here, can this kind of setup work?Btw I have my nat sip aware. Also can I implement the pstn gateway without using any database like mysql or postgre?
Feel free anyone to reply.
Thanks!