What is phone off-hook?
What is phone off-hook?
The state of a telephone line that allows dialing and transmission but prohibits incoming calls from being answered. The phone is off-hook when the handset is lifted off the base of a stationary phone or when Talk is pressed on a portable phone. The term stems from the days when the handset rested on an actual hook.
What happens when a telephone set is taken off-hook?
Off-hook describes a state that a phone currently is in when the phone is taken off the hook or placed in the off-hook position. Off-hook causes the phone line to be busy and allows the user to place phone calls or answer incoming calls.
How many volts does it take to make a phone ring?
Ring signal: A ring signal is generated by the exchange to indicate an incoming call. It consists of bursts of low frequency AC voltage across the line, typically 90 volts RMS at 20Hz (North America) 60-90 volts at 25Hz.
What is on-hook and off-hook?
In telephony, on-hook and off-hook are two states of a communication circuit. On subscriber telephones the states are produced by placing the handset onto or off the hookswitch. Placing the circuit into the off-hook state is also called seizing the line.
What is off-hook ringing?
phrase. If your phone is ringing off the hook, so many people are trying to telephone you that it is ringing constantly. Since war broke out, the phones at donation centers have been ringing off the hook.
How do you tell if a phone is off the hook?
Listen for a ring or a busy signal. If the line is open, you’ll hear the line ringing. If you hear a busy signal, it’s likely that someone is using that phone line. You’ll also get a busy signal if the phone was accidentally left off the hook or someone else is dialing the number at the same time you are.
What do you mean by off-hook and on-hook condition?
Is a phone line AC or DC?
These two wires provide: DC current to power the telephone electronics, AC current to ring the telephone bell or electronic ringer, full duplex balanced voice path. This is a closed loop, balanced system not referenced to earth ground. The POTS phone line, with all phones on-hook, should measure around 48 volts DC.
Is ringing voltage AC or DC?
Typically, the ring conductor has a direct current (DC) potential of −48V to −52V with respect to the tip conductor when the line is in the on-hook (idle) state.
Can phone lines electrocute you?
While telephone lines do have 48 volts of electricity running through them, it’s usually not enough to cause a shock, though it may affect a pacemaker. The electricity in a phone line does spike to around 90 volts when the phone rings, which can give a mild shock.
Do phone lines have voltage?
The POTS phone line, with all phones on-hook, should measure around 48 volts DC. This drops down to the 3 to 9 volt range when a telephone on the line goes off-hook. An off-hook telephone typically draws about 20 milliamps of DC current to operate, at a DC resistance around 180 ohms.
What does off hook mean on a telephone?
When off hook the weight of the receiver no longer depresses the spring-loaded switchhook, thereby connecting the instrument to the telephone line . Off hook telephone. The term off-hook has the following meanings:
What is the meaning of off hook condition?
When an off-hook condition persists without dialing, for example because the handset has fallen off or the cable has been flooded, it is treated as a permanent loop or permanent signal . The act of going off-hook is also referred to as seizing the line or channel.
How do you know if a phone line is off hook?
On an ordinary two-wire telephone line, off-hook status is communicated to the telephone exchange by a resistance short across the pair. When an off-hook condition persists without dialing, for example because the handset has fallen off or the cable has been flooded, it is treated as a permanent loop or permanent signal.