The railway began with one telephone line at Alresford, 0962 3810, as business grew additional lines were added and a Key and Lamp system (KLU) was introduced. Until the introduction of a System X exchange at Alresford it was not possible to have auxillary lines on 3810, so a number of single lines were added, one of these was 0962 4200 which was listed for a time. 0962 3810 later became 733810 with the new System X exchange and would become the main directory number as auxillary lines could now be added. 734200 as it was then, remained but not listed in the public domain, it was found years later people were still calling this number, it was never possible to establish where the number was still being obtained from.
The number of KLUs grew to a maximum of 15, the system worked well but there were two problems.
The introduction of computers and swipe machines needing access to exchange lines and the complexity of the KLU wiring, each unit having a 25 pair cable connected back to the KLU relay sets via a Box Connection 3A which was installed high up in a store cupboard, it was in an awkward location for working on and fault finding.
from Turntable December 8th 1984
The first problem was solved by the introduction of small BT 2+8 switches, 2 exchange lines and 8 extensions. The second by completely re-wiring the KLUs onto a modern Box Connection 502 using Krone strips located in a more accessible location.
Station Box Connection - included the terminating point of 15 KLUs.
Shown below is the Box Connection in Alresford exchange, at one point 3 exchanges were connected. The Strowger for internal calls, a Panasonic 1232 for external ones and the Norstar which replaced the other two. 
Another wonky picture, the box is upright - blame the photographer!
The strips on the left coloured red are fitted with lightning protection strips.
This replaced a standard MDF with soldered connection blocks, it can be seen in the background of the picture on the Home page. An example of the type of block is shown below, picture taken at the Dean Forest Railway of a 50 pair block.
100 pair IDC block that replaced the solder type shown above, this one was recovered from Medstead when a Box Connection 502 was provided.
Takes the same amount of space as the soldered block. Another type of IDC block has Gas Discharge modules fitted for lightning protection.
One day I had a chance conversation with an office manager and enquired what he intended to do with his Panasonic 1232 exchange that had just been replaced, when told he intended “to kick it round the car park” it was suggested a new home could be found for it, donated to the railway it replaced the KLUs at Alresford.
There it remained giving excellent service until replaced by the Norstar system; it is now doing further service on the Festiniog Railway at Harbour Station where it also replaced KLUs.
Shown in its new home in Wales, the box at the bottom is an inverter that converts 50 volts DC from the Strowger exchange standby battery to 240 volts AC to run the switch.
As other stations opened and required external lines the BT 2+8 switch was used, these gave good service until a new version swipe machine was introduced.
The problem was discovered shortly before a major event when a couple of swipe machines would be busy all day. There had been no problem before with the previous swipe machines it was just the new variant that didn’t work.
On ringing the swipe machine help desk and asking if there was a compatibility problem with the 2+8 and the new swipe machines I was informed helpfully “yes and no”.
Norstar equipment then became standard for external lines.
Other exchanges used in the past have included the BT Renown, BT Revelation and the BT Ultimate 106.
Box Connection 3A after recovery.
Box Connection 2A in the station office at Alton, one of the few soldering connection blocks on the railway, it was replaced with a Krone Box Connection 301 in 2008 during a refurbishment of the office. Home