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.
Rough sketch of the connections of the KLUs, the diode matrix was provided as some KLUs needed an indication of incoming calls on some lines but not others, some KLUs didn't need any indication of any incoming calls and each needed indication of their own internal calls.
Any keys left operated without a call connected would result in the KLU buzzer sounding after a short delay, removing the problem of wandering around and checking all KLUs to see who had left a key thrown.
Out of hours an incoming call could be answered by any extension by dialling 8.
A problem of transferring an incoming call answered on a KLU to a remote phone without a KLU was overcome by the transfer relay set connected to level 24. The call was answered and the required extension informed there was a call on line 1 or 2. They then dialled 2411 for line 1 or 2412 for line 2 and were connected to the incoming call. There were not many calls of this nature so this arrangement was sufficient.
Incoming calls were counted on meters, plus how many were answeed.
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 red strips on the left 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 520 was provided.
This takes the same amount of space as the soldered 50 pair block. Another version of the 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, it was donated to the railway and replaced the KLUs at Alresford.
This was a very good system with a capacity for 12 exchange lines and 32 extensions.
Each extension port is a 4 wire circuit, this allowed one to connect either a system phone with lots of extra facilities which needed a 4 wire connection (part of one can be seen to the left of the picture below) or a basic 2 wire phone, swipe machine or fax.
Programming the system could be either done from the extension connected to the first port or by using a PC, we didn't use this method as at the time we had it didn't know the facility existed.
It gave excellent service until replaced by the Norstar system; it then moved to the Ffestiniog Railway at Harbour Station Porthmadog, where it also replaced KLUs in the Control Office.
Shown in its new home in Snowdonia, 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.
Station 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