Norstar
With an increase in the number of computers and swipe machines requiring dial up connections the Panasonic 1232 installed at Alresford had reached its maximum capacity and was replaced with a Meridian Norstar 032 switch.
Eventually this grew to an installed capacity of 8 exchange lines, 48 digital extensions (32 on the main switch and 16 on a MOX16) and 16 analogue extensions which are fed from two Analogue Extension Modules (AEM)
Alresford is the administrative centre of the railway and deals with all public enquiries and bookings.
Prior to a special event incoming phone traffic was very busy, the introducion of on-line ticket booking service has made a difference to the number of incoming calls received.
Work started at Ropley, this is the engineering centre of the railway, installing a Norstar Compact Plus to replace a BT 2+8, this was deferred as various site changes planned might have required additional extensions, when work resumed at a later date a Norstar 032 was installed giving a maximum of 4 exchange lines, 32 digital and 8 analogue extensions (1 AEM).
One early idea was to link the Alresford and Ropley Norstar switches as these two stations generated the most calls between the sites, key users would be provided with Norstar extensions.
Alton and Medstead each had Norstar Compact switches installed with 16 extensions, any analogue circuits needed an Analogue Terminal Adaptor (ATA).
The railway had 2 independent telephone systems, 4 Strowger exchanges used for inter railway calls only and 4 Norstar switches for external calls but also capable of handling internal calls, a decision was made to use the Norstar switches as the sole telephone system.
A new plan was drawn up using a 3 digit linked numbering scheme, due to the flexibility of the routing arrangements only 3 digit numbers are required.
Locations common to stations would have the last two digits of the number the same - all signal boxes are X31, shops X44, this was based on the numbers in use at the time on the Alresford Panasonic switch.
New numbering scheme - Alresford 2XX, Medstead 3XX, Alton 4XX and Ropley 5XX.
The first digit was the planned order the exchanges were to be placed in service but due to various reasons they were not installed in the order originally planned.
There are around 90 extensions with phones and another 20 extensions for swipe machines and other miscellaneous circuits.
In keeping with tradition there is a test number on X99 and the exchange phone is X90.
All four sites have call loggers and Startalk, this allows external callers to contact an individual extension without an operator being involved.
AC15 circuits links connect the exchanges, each AC15 circuit fitted reduces the extension capacity by 1. The Compact units at Alton and Medstead only had capacity for two AC15 circuits, as there was a minimum requirement for 2 circuits between exchanges the equipment at Medstead was replaced with a Norstar 824, giving 24 digital extensions and a maximum of 16 AC15 circuits although only four were required, two to Alton and two to Ropley.
Due to the arrangement of the circuits Medstead acted as a tandem exchange, it was not possible for the ideal arrangement of one exchange being directly connected to the other three.
Medstead Norstar 824, Startalk and MOX16 plus BT 2+8 - neither switch now in service
Alton was later changed to a Norstar 824.
For some time the two systems ran in parallel and some staff members continued to use the old system so the number of Strowger circuits between stations was reduced to the minimum to create congestion and force the new system to be used as there was a need to shut the old one down and utilise the cable pairs its junctions had used. It has been found that some individuals prefer an ancient relic that does not work correctly to a modern one that does.
One suggestion was to modify a Norstar phone so it had the appearance of a wooden phone, an idea that was never pursued.
The Strowger system was closed down at the end of 2004 pending disposal although unknown at the time it was not to be the last of this equipment on the railway.
In the early days of the Norstar switches the redundant BT 2+8 exchanges were used piggy backed on the Norstar switch for the low usage analogue extensions, with the availabilty of additional AEMs these exchanges were later withdrawn and the extensions moved directly to the Norstar.
Alton Norstar 824 switch was replaced on March 25th 2006 and Medstead Norstar 824 on 29th July 2006 with Norstar 032 units, each has a maximum capacity of 4 exchange lines, 32 digital and 16 analogue extensions.
Alton - Call logger, box connections 301s, Norstar 824, Startalk.
Top right are analogue terminal adaptors and AC15 units.
Top left is the unit housing the 50 volt to 24 volt converter for the carrier rack, with an amplifier on top.
Alton 032 being installed, also shows 2 AEMs and the Startalk unit.
The small box with the white label is the remote alarm to Alresford.
Ropley exchange was moved from its existing home in the station building on 24th February 2005, with the recovery of the Strowger far less space was required, it is now situated in the station house.
Ropley - from the right Norstar 032, 2 AEMs and a MOX16. Startalk above
Fitted from the outset with a capacity of 4 exchange lines, 48 digital and 16 analogue extensions. The old exchange room has become a disabled toilet.
One disadvantage of the AC15 circuits is that they require 2 pairs of wires, transmit and receive. This reduced the number of direct circuits that could be provided due to the limited number of cable pairs available, another disadvantage is if one pair of wires went faulty the distant exchange equipment wouldn't be busied out of service and subsequent calls would fail.
The AC15s were later connected via analogue to digital conversion units, these have the advantage of only needing one pair of wires also if the circuit becomes faulty both ends are busied out of service.
A new digital trunk network (DTN) was installed working along side the analogue AC15 circuits, with the new circuits requiring only one pair of wires more direct circuits could be provided between switches, Ropley has direct circuits to the other 3 exchanges as does Medstead, Alresford and Alton have circuits to two other exchanges.
Traffic was moved to the DTN and the analogue circuits were then withdrawn from service creating more spare cable pairs for other servces.
Alresford/Alton traffic tandems through Ropley or Medstead depending on the direction of the call, the sole reason for no direct link is the digital units will not work the full 10 miles of the line. There is a way of overcoming this problem but as this is the route with the least amount of calls it isn't worth the effort.
Two sites have a recovered Compact model fitted, these are used solely for testing purposes, such is the flexibility of the numbering scheme both switches are in the 4XX number range. These days it seems exchanges must have names so one is called Wallace and the other Gromit.
The system has proved to be very reliable with better transmission standards between stations, no noisy calls due to dirty selector banks.
There have been a number of cases of exchange isolation but this has always been due to power failures and no one acting on "mains fail" alarms and the batteries discharging after a period of time.
Phones have given most problems, sticky keys being a common fault along with noisy handset cords.
One minor problem with the Norstar system is that on trunk calls the first circuit is always selected, if this was faulty problems could be experienced
To overcome this a diverse route code has been added if there are difficulties on a route.
For example if there were difficulties on the Ropley to Alresford route by adding a two digit code to the three digit extension number the call would be routed Ropley to Medstead then Alresford. One code covers all exchanges but this arrangement is of no use if the cable is cut between stations.
One issue that came to light in the early days was reports of "trouble with the phones at Alton" but never anything more specific, several visits were made with no problem identified but then one didn't know what to look for. Eventually a report was made by a reliable source stating phone X couldn't dial either phone Y or Z. Further investigations were made, phone X was on the platform and was an old style dial model, phones Y and Z contained the digit 1 in their number and to cut a long story short it was found a dial phone on a Norstar switch cannot dial the digit 1, the timed break recall condition it was later realised. The few dial phones in service were replaced by MF models .
Another problem was the introduction of chip and pin technology, swipe machines were connected via AEM ports. Once PINs were used some swipe machines worked while others connected to the same exchange didn't, after some experimentation the solution was found to connect all swipe machines via an ATA2, this solved the problem.
Ropley - Norstar 032, one AEM in the old exchange room, also shown are 2 AC15 units. 7100 and 7310 phones
Change over from old to new exchanges.
From the main distribution frame on the left temporary jumpers connect to the small Krone block in the centre of the picture, there the circuits run via a temporary 40 pair tie cable to the new distribution frame on the 1st floor in the main station building - seen in the picture below.
External and internal cables were then diverted from old to new exchange one at a time.
Another view of Ropley showing the Krone connections
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