This isn't a cold call

"Well it is sort of", said the man from Global Telecoms and Technology. Apparently BT are changing their entire system to "IP Technology" (which they are) and as a result the current equipment we have won't work. What we need is a DMIcP box, which fortunately this company can supply.

"But we're not with BT", I state.
"Doesn't matter; everyone runs through the BT system", came the reply.
"But this upgrade is predominately exchange to exchange"
"Ah but they're upgraded the ISDN lines and it won't work"
"We don't have ISDN"
"What do you have?"
"Normal PSTN plus copper wiring"
"Ah no it won't work with that either"
"Yes it will"
"Well would it be alright to send a Business Manager over"
"Um no"
"Oh okay then bye"

Okay to be fair some positively ancient equipment might not work and you almost certainly need new equipment to access the new services, but can you imagine BT telling every single telephone user in the country that they need a new telephone because their old one will stop working shortly? But hey don't take my word for it

"BT expects the vast majority of customer premises equipment (CPE) used to access services today will work normally on 21CN"

Ah-hah here's a graphic representation. What this doesn't show and what I failed to mention is this doesn't affect LLU's that is if you're not paying your line rental to BT.