Past Development
1948
Emerson central office was first established with No. 1 crossbar equipment at 1249 E. 145th Street.
1950
Second unit of No. 1XB was started.
1956
No. 5 crossbar was initiated in the Seattle exchange as the third unit at Emerson. The tandem feature of No. 5 unit used for EAS between Seattle northend offices and West Coast Telephone Company SXS fringe exchanges.
Toll terminal established for protection and restoration purposes.
1958
Emerson XB Tandem established in existing building. Use of #5XB unit for tandem switching discontinued. 2L-5N dialing established.
1961
DDD/CAMA established.
1966
ANI installed.
Future Development
For the current view of future developments, please refer to the Seattle section of the "Planning Guide issued by the District Engineer – Planning.