Canadian Agricultural Products. To check for restrictions on fruits and vegetables from Canada, you can search the FAVIR database at www.aphis.usda.gov/favir/. Click the âFresh Fruit and Vegetablesâ link to the right to learn how to use the database.
The standard voltage for the telephone system is 48 volts DC. Ringing voltage is much higher, around 90 volts AC at a low frequency. When you place a load of about 600 ohms on the line, you are off hook or connected. Telephone ringer voltage is 50.5 volts at standing and -50.5 volts at ringing.
Phone lines normally run on -48v DC (referenced to ground) when the line is idle. During the ringing cycle (in the US, 2 seconds on, 4 seconds off), a ringing voltage of 75-90v AC (typically 20 Hz in the US) is superimposed on top of the -48v DC.