I'm on a conference call to BT where Steven Evans, the head of wireless broadband, is talking to us about their new enterprise product. It is - or will be, when launched -- a Wi-Fi/GSM phone that can switch between the wireless LAN in the office and GSM networks outside. Jolly good.
"The enterprise can decide to give the phone either a fixed or mobile number," he says. "With the fixed number, the call comes into our presence server which works out whether the phone's on a LAN or not, and if not the call is routed via the GSM network. That can save money, because people normally divert their desk phones to their mobiles when they're out of the office. The system saves tromboning."
Tromboning, gentle reader, is the rather descriptive term for when a call is routed through to a number only to find that it has to go somewhere else -- it happens a lot in roaming. So the call has to go sliding out again to its real destination. It's not a good thing to happen, because there are two legs in the call that don't contribute anything except expense.
"I see," I said. "So if someone calls in on a fixed number, they'll still pay the fixed line tariff even though the call is being routed on the mobile network."
"So who pays for the mobile leg?"
"The company pays for that"
I'm getting confused now - it looks as if BT gets two slugs of dough, one on the incoming call and one on the mobile leg. Who's saving the money? And then if the phone is given a mobile number but is really in the office on the LAN, the caller pays full mobile tariff with the company paying for the infrastructure to deliver the wireless bit. No wonder BT thinks this is a great idea. But perhaps I'm missing something: it is easy to get confused when you've got three interconnecting networks of landline, mobile and IP, and multiple choices of delivery mechanism.
"Hmm," I say. "Have you got any documents you can send me about this which set out how this works?" A decent diagram is worth a thousand words, even when they're uttered by the Head Of Wireless Broadband on a conference call.
"Er, we can perhaps pull something together. But we're used to talking to journalists who understand these things"
Oww. That's telling me. For enlightenment, I turn to a broadsheet report on the same launch (no names, no pack drill, honour amongst thieves, etc) which clearly does "understand these things". BT to replace the desktop phone, it says. Will save companies thousands. Defeat spiralling call costs. New technology, first in the world. Dawn of hope and joy to the world.
Just goes to show, even after twenty years covering telecommunications there's still lots to learn. Like don't ask awkward questions if you don't want to be treated like an idiot.
At least I get to share my idiocy -- and the wisdom of BT -- with you lot.