Getting started with outbound calls

I am looking at integrating asterisk to my PSTN line in order to be able to place outbound calls from my PC to mobiles, etc from my fixed line phone.

I have an HT503 ATA that I have used earlier a long while back with FreeSWITCH, but I have no recollection of how I had used it.

Any guides, tutorials, or general advice to help me get started is very welcome!

You can use physical cards, if you use Digium you will get commercial support. In case you cant use physical cards you can use a FXO Gateway I 'm currently I’m using a Grandstream-GXW4104-4-port-FXO-gateway

I do have a HT 503. Is there any guide I can follow to get it to work?

HT 503 it is a cheap device, sound quality and performance in my personal opinion it is not recommended for a production environment, If you want to find a configuration guide to this device you will need to figure your self as we dont support any hardware on this forum