The 81-a exchange trunk carrier system -Applications

Continuing programs of service improvement by the telephone operating companies have sharply increased the demand for telephone circuits in recent years. For the long-haul applications, carrier systems have been used extensively to satiate this demand. However, for short trunks of 15 miles or less, circuit expansion has almost exclusively been obtained by the expansion of the cable plant. Since a major portion of the requirements for new short-haul circuits exists in the large metropolitan areas, the installation of new cable is often difficult as a result of conduit congestion.