How many civil servants does it take to...?

Pandemonium ensued at work yesterday, when a terrifying thing happened:

It was lunch time, so luckily the office was only approximately half-staffed, otherwise I dread to think of the chaos that could have occurred. An animated, yet quiet conversation was taking place between a couple of the Work Hags, two managers were discussing something boring at their adjacent desks and the rest of us were getting on with our work.
Suddenly, a shrill, piercing, alarm sounded twice in quick succession. Then a pause and it sounded again. Another pause and the alarm went off again.
The Work Hags immediately ceased their chatter, their heads snapping around in the direction of the strident alarm. The managers also stopped talking, one of them standing up to see over the baffle board in front of their desk. All over the office, heads rose from desks, popping up like meerkats after sensing danger, all the while, the alarm kept sounding.
It wasn't the fire alarm, and it certainly wasn't the bomb alarm. Instead, it was something that's very rarely heard, something from a bygone age. Something that we had almost forgotten.

"Shit" said one of the Work Hags. "That phone is ringing!" And she pointed to the desk next to hers in almost abject horror.

Confusion reigned as questions and hypotheses were fired back and forth as to what could be causing this infernal noise to emanate from the telephonic machine. The managers didn't have an answer. They just looked at each other helplessly.
The other Work Hag, after much wailing and gnashing of teeth, suddenly cried: "Who is it?"
Someone gingerly approached the telephone and looked at the caller display screen.
"I don't recognise the number" they said.
"Why is it ringing? Why?!"
Then it stopped. The silence was blissful, but it didn't last, The phone continued to ring again. And again. And again!

I looked over my computer monitor, rolling my eyes. "Why don't you just bloody answer it?!"

- - -

Ever since we had a new phone system installed that's linked to the computers, everyone's had to wear headsets, which when we're logged into the system, beep to signal an incoming call. We've only had this set-up for a couple of months, but we're now so used to not hearing phones ring, that when one does start its incessant caterwauling, because someone unplugs their headset and forgets to log out when they leave their desk, we're practically helpless as to figure out what to do.

Pah!