GPO Telephones - Plans 105 & 107

Plans 105 & 107

These were updated versions of the 200 type plans 5 & 7 but based on the 700 type telephone. It had a master station which was a 700 type telephone mounted on a plinth with buttons, 'The Planset'. The master station and the extension stations could call and speak to each other and also handle and transfer outside calls. The difference between a Plan 105 and Plan 107 was that the latter had only one extension; the former had two. On plans with the 'A' suffix, conversation between the extension and the exchange was private against the planset. On a Plan 107 both of the long buttons, on the front of the Planset, were connected together. Pressing either would 'buzz' the single extension.

The Plansets were available in Black, Ivory and Grey, to match the three colours of telephone officially specified. However, many customers opted for contrasting case, planset and handset colours.

As with the HES3, the installing engineer would have to requisition all the elements separately and assemble them on-site, from an array of packaging. With its case removed, the master instrument was then screwed down onto the Planset whilst squeezing a thick umbilical cable up through the oblong hole in the telephone baseplate. This was very difficult to achieve without damage to the wiring. The hole left in the rear of the telephone case, by the removal of the, redundant, instrument cord, now had to be filled with a matching coloured, square bung.

• A Plan 105 master station in need of TLC

• A Plan 105 extension showing the call button