But as far as I can tell, the built-in pager system does not work "out of the box."  The docs devote roughly a single paragraph to the SNPP/pager setup.  Basically it says put in the phone number of your device (i.e. my cell phone since nobody has pagers these days). Using the "test" function yields a "Test failed: socket.error - (111, 'Connection refused')" so that's of no use at all.  There's no troubleshooting info in the admin guide to take you past this point, or at least none I could find by searching for "SNPP" and "pager" through the whole PDF.

After spending some quality time with Google, it looks like Sendpage may be one of the better options for getting a modem hooked up and sending SMS messages using a TAP dial-up gateway.  Now the question is how to implement this within Zenoss without spending the next two weeks messing around with scripts and such.

I'm off to search the Zenoss forums for specific examples.  Hopefully I'll find something that can get me started. If I get it working I'll try posting how I did it.  Web-based SMS gateways are quick and easy but are of no use at all if your connection fails.  Hence the modem and a good old reliable POTS line.

I see your point, but in the last three years our T1's have been down quite a few times.  POTS lines?  Never.  Not even once.  Shocking but true.

What I'm likely going to do is use a combination of either SMS-via-web, SMS-via-POTS, and offsite monitoring (pings and/or heartbeats) to ensure we always know when something drastic has happened.  The SMS-via-POTS is (apparently) the most difficult to implement so I'm trying to get it out of the way first.