SIP can be very interesting / fun once you get the hang of it! I agree with other comments though that starting with a Cisco 79xx is a rough way to start. A soft phone or Cisco/Linksys SPA 9xx or any yealink phone is a great starting point.
Kamailio is also an aggressive starting point. There are several open source options that might be a bit more friendly to start with.
SIP can be very interesting / fun once you get the hang of it! I agree with other comments though that starting with a Cisco 79xx is a rough way to start. A soft phone or Cisco/Linksys SPA 9xx or any yealink phone is a great starting point.
Kamailio is also an aggressive starting point. There are several open source options that might be a bit more friendly to start with.