Initially, the system provided data connections to replace the ones that had been lost in the building work, which consisted of a mixture of IBM3270-style terminals, RS232/V24 asynchronous connections to X25 PADs, and Apple Localtalk connections, as well as a few Twisted-pair Ethernet connections. The planning had foreseen provision for 24 Ethernet ports at each of the two Patch Centres (Hubs).
The IBM terminals were phased out by Autumn 1994, and the X25 PAD lines have been phased out with a few exceptions. By now (Autumn 1995) the great majority of connections are to Ethernet, to the extent that there are now 72 additional ports provided at each of the patch centres in addition to the original provision of 24 ports at each, and most of these are in use, to say nothing of a few stand-alone hub modules that are deployed in individual rooms or labs. And note that this is not counting the Undergraduate PC clusters, which still use a local co-axial daisychain (unfortunately). There is a small but steady demand for Localtalk connections.
Some Statistics: --Patch centres-- Total
================ level 2 level 4
Number of racks 2 3 5
Room sockets (doubles count as 2) 386 540 926
Available service ports (approx., as at October 1995):-
--------------------------------------------------------
Ethernet 96 96 192
Localtalk (Phonenet) 22* 11* 33*
(*)each port can serve several users
X25 JANET PAD (CAMTEC) 14 15 29
LAT terminal servers (NS group) -- 16 16
This table shows the number of available active ports at the patch centres only. Not all of the available ports are actually in use, in fact the number of PAD lines connected is decreasing, and some of those connected are not actively used.