Review of trunk transmission planning in the UK Post Office

The UK trunk transmission network, which provides transmission facilities for the public switched telephone service and other services, is rapidly expanding at a time when digital forms of transmission and switching are being introduced. A plan for the changeover from analogue to digital transmission systems to meet network growth has been formulated and is now at the detailed planning stage. A 10-year changeover period is envisaged, to provide in the 1980s an extensive digital transmission network for the trunk services.