GWR Route: Banbury to Wolverhampton
GWR Route: North Warwickshire Line
Birmingham Snow Hill: gwrbsh3013
An early Telephone Exchange room at an unidentified
location. There are two exchange desks in the room. The one being used by the
operator appears to be a public telephone exchange desk. The layout can be
identified from the top as:
- Six glass discs - indicating each Junction Line, with
those connected being illuminated. Junction Lines are the external connections
available to receive (or send) calls from (or to) the General Post Office (GPO)
public system on a single telephone number.
- Three rows of nine glass discs - which when
illuminated indicate that an external call or an individual extension line is
calling the exchange. The first six discs on the top row appear different, so
these probably indicate the Junction Lines. The remainder are the possible
internal extensions (maximum twenty-one) that could be connected to either the
public system (up to a limit of six) or to any other internal extension. These
would be for the commercial and railway departments.
- Three rows of nine extension line plug sockets -
corresponding to the Junction and Extension line indications above.
- Desk - to holds ten jack lead loops for connecting to
each pair of Junction or Extension line sockets plus a spring loaded switch,
which presumably is used to select a line for the operators
Notes: The clock allowed the operator to record the time of
all the outgoing calls.
According to a Great Western Railway Magazine article in
August 1911, the original public telephone exchange at Birmingham Snow Hill had
six Junction Lines and eighteen Extensions, so the telephone exchange equipment
would have been similar (see
Hill Telegraph and Telephone development Articles). This was prior to its
replacement with a new combination multiple switchboard.
The other telephone exchange desk appears to connect to the
various omnibus lines and there is no connection between these and the Junction
or internal Extension lines on the public telephone exchange system. Any long
distance Trunk lines would also have been connected to this telephone exchange
desk. There are two rows of ten glass discs with a plug socket directly below
each and as before the desk holds eight jack lead loops, which are weighted to
keep them hanging straight with a switch for each loop. Adjacent to the
equipment on the wall there are four omnibus telephone circuit cards (see
equip234) and several bells, including one associated what appears to be a
twelve-way selective system telephone. The Great Western Railway developed
these twelve-way selective system telephones but found that the complex
arrangement resulted in cross ringing and that an eight-way selective system
telephone was more reliable (see misc_equip233).
In the corner on the desk behind the operator is an electric
telegraph hand set for tapping out messages in Morse code. For more information
about Railway Telephones see 'Railway