Winking is a

telephony signaling In telecommunication, signaling is the use of signals for controlling communications. This may constitute an information exchange concerning the establishment and control of a telecommunication circuit and the management of the network. Classif ...

technique used both in connection with DC signaling on a trunk, and with indicator lamps on a

key telephone Key or The Key may refer to: Common meanings * Key (cryptography), a piece of information that controls the operation of a cryptography algorithm * Key (lock), device used to control access to places or facilities restricted by a lock * Key (ma ...

. In

telephone switching telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syste ...

systems, wink pulsing is recurring pulsing in which the off-condition is relatively short compared to the on-condition. In wink start trunks, the exchange at the originating end sends an

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 th ...

to alert to a call. The terminating end indicates readiness to receive the dialed

telephone number A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices f ...

by sending an off-hook of approximately half a second duration, or "wink". Upon receiving this go ahead signal, the originating end uses

multi-frequency In telephony, multi-frequency signaling (MF) is a type of signaling that was introduced by the Bell System after World War II. It uses a combination of audible tones for address (telephone number) transport and supervision signaling on trunk lines b ...

or other address signalling to send the phone number. On 1A2 key systems or similar key-operated telephone instruments, the hold position, ''i.e.,'' the hold condition, of a

line Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Arts ...

is often indicated by winking the associated lamp at 120 impulses per minute. During 6% of the

pulse period In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the ne ...

the lamp is off and 94% of the period the lamp is on, ''i.e.,'' 30 ms (milliseconds) off and 470 ms on.

References

* {{telephony-stub Telephony signals