Interlocal manual switchboard
After the completion of the post office, a manual switchboard was set up in 1926 for telephone traffic with places outside the city of Utrecht. This manual switchboard was located on the second floor and was operated by telephone operators. Anyone who wanted to call someone outside Utrecht requested the call from the operator, giving the place and telephone number. As soon as the operator had prepared the connection, the person was called back and the conversation could begin. The waiting time for such a conversation could vary from hours to several days. The number of connections with other power stations was still very limited. In the beginning there were 200 connections to the manual switchboard. With the help of 90 shift operators, an average of 6,000 long-distance calls were made per day. Just before the outbreak of the Second World War, 160 telephone operators worked in shifts. After that, the number of telephone operators decreased to zero in the 1960s due to automation