Just moved into a new (c.1951) house. Only one jack is working, in the kitchen.
Three phone jacks are not working. They've all been similarly wired (all yellow/red/black/green wires connected), however, they were not wired to the colors designated on the jack. The screws holding the red wires all have white deposits on them.
How can I spring some life into these jacks? Is telephone electricity something with which to use caution? Is there a way to test if they are getting juice?