Communicating With Base Station

. Is it possible to log into the base station using HTTP or Telnet? - NO

It appears the online web interface and the iPhone app does not do anything unless subscribe to the remote monitoring service.- With $24.99 plan only..

I received my SS3 system about a week ago, and I have not subscribed to any service plan yet.  Going into the router/modem logs I see that the base station IP reaching out to a destination address on the WAN.   . the destination address changes sometimes, the time out response parameter is set to a very large value..28800 or so...but the port number of 8899 is constant.  

Could this be the 'Heartbeats' which was introduced in SimpliSafe 3. ...i.e the Base Station regularly check your sensors and devices to ensure everything is working properly and "phones home" this status.  (Again, I'm not subscribed to any service plan presently)

SS is using Amazon Web Services (AWS) like every body else practically.  The IP destination may change periodically as the base is likely looking for a site name via DNS, not an IP address.  I've never really paid attention to it, but mine at the moment is talking every few seconds.  Likely it's an internet watchdog check.  If it fails it knows to switch to cell backup.  The health check itself happens once every 24 hours.  During this check it tell SS that its working fine and tells them what you ate for dinner.  -kidding.