PPP direct dial in

If I want connect my notebook computer to a remote RAS server, (using PPP), do I directly dial into the RAS server or do you have to first dial into an ISP?

I know that with PPTP, you have to dial into an ISP. But if you are not using PPTP, canyou directly dial into a RAS/PPP server, or do you have to first dial into an ISP?

Thanks

Tony