Story is that Bell tested the T1 in comms pits around Murray Hill NJ and when it worked for a long city block between two manholes they knew they had a product they could sell.

Watched a telco guy fix a broke E1 by sending one of the pairs a bit further round the krone frame to separate the signals better. I've even seen them add more wire to try and dampen down some local noise or reflectance or harmonics or something.

The old E1/T1 lines were sometimes pressurised and came with fancy brass taps to let the water out with its own teeny weeny bucket hanging off the tap. I kid you not.

A book I have says the eighth bit was initially used to indicate on-hook/off-hook status, not framing.

Our block of phone numbers (we had a block of 500 or 1,000 numbers) was tied to the PRI T1s; for the CAS T1, we were allowed to use our number block as the "calling party" number for outgoing calls. If the PRI T1s went down folks wouldn't be able to call us, but we could call them and the called parties wouldn't notice any difference.

A gallon is two pottles; a pottle is two quarts; a quart is two pints; a pint is two cups; a cup is two gills. And a gill is two jacks!

24 and 4 don’t strike me as unusual numbers (two dozen and two doubled), but seven does.

> a different media

‘A … medium.’ One medium, two or more media.

> A DS2 is a combination of 4 DS0s, for 96 channels or 6.312Mbps.

What sorcery is this? How can 4 DS0 lines provide more bandwidth than 24 DS0 lines?