No. 2 ESS Unigauge Range Extension

Range extension allows the No. 2 electronic switching system (No. 2 ESS) to serve subscriber loops out to 2500 Ω as part of the Bell system's unigauge plan. Range-extender circuits provide both audio and dc gain for loops greater than 1300 Ω. These circuits have been designed specifically to be low cost, as small as possible, and to use minimum power. Network concentration allows 70 percent fewer range extenders to be provided than customer lines served. All trunk, service, and test circuits that had to be modified to work range extended are provided on a standard basis in every No. 2 ESS office. This means that range extension can be provided in a No. 2 ESS office at very low cost; essentially the cost of the range-extender circuits.