Auditory Apparatus

An auditory apparatus component is one instance of a source and destination of speech-quality media streams.

Though typically an auditory apparatus consists of both a microphone and a speaker, it need only have one or the other. An auditory apparatus usually is one of the following types:

• Handset

A handset is the most common type of auditory apparatus. It is a straight or elbow-shaped device that is held in a person's hand, with a microphone at one end and a speaker at the other.

• Headset

A headset is an auditory apparatus that is worn on the head. It has both a microphone and speaker. The microphone may be on a boom of some sort or built into the ear piece.

• Speaker phone

A speaker phone auditory apparatus is the combination of a microphone and a speaker built into the base of a telephone set, or arranged in some other fashion to allow for untethered operation.

• Speaker-only phone

A speaker-only phone is an auditory apparatus that is like a speaker phone but has only a speaker and no microphone.

A physical element may have any number of auditory apparatuses. Every auditory apparatus is associated with exactly one hookswitch^4-3 (although a single hookswitch may be associated with more than one auditory apparatus).

4-3 Hookswitch devices — Because auditory apparatuses are governed by a hookswitch, they are called hookswitch devices by some.

Microphone

A microphone allows sound to be converted to a media stream for use in the telephone system.

Microphones have two properties:

• Mute

Microphone mute determines whether or not the microphone is active.

• Gain

Microphone gain determines what amplification of the captured sound is applied.

Speaker

A speaker allows a voice media stream from the telephone system to be converted to sound.

Speakers, like microphones, have two properties:

• Mute

Speaker mute determines whether or not the speaker is active.

• Volume

Speaker volume determines what amplification is applied to the sound.

4.1.3 Hookswitch

A hookswitch is a component that determines what auditory apparatus or set of auditory

apparatuses are in use. A hookswitch can be either on-hook (inactive) or off-hook (active). If a hookswitch is off-hook, every associated auditory apparatus is actively consuming and/or generating sound. If a hookswitch goes on-hook, every associated auditory apparatus is made inactive.

A physical element may have any number of hookswitches and each operates independently of all the others (Figure 4-3). A hookswitch may be a spring-loaded switch on the telephone, it may be a single locking switch that is pressed to set it off-hook and pressed again for

on-hook, or it may be a pair of switches where one is used to go off-hook and another is used to go on-hook. It also may be an internal (or virtual) switch.

Figure 4-3 Hookswitches

4.1.4 Ringer

The ringer is the component in the physical element that notifies people when the telephone system is attempting to connect a call to a logical device element,^4-4 with the intent that it be answered by the physical device in question (i.e., a connection in the ringing mode of the alerting state is present) or when the telephone system is prompting.^4-5

4-4 Multiple logical device configurations — The relationship between physical and logical device elements is described in section 4.5. Every operational physical device element is associated with at least one logical device element, but it may be associated with two or more.

4-5 Prompting — The prompting feature is described in Chapter 5. It refers to a feature where the

telephone system is unable to make a physical device element go off-hook automatically and must signal for a person to do so.

The ringer has a bell or buzzer to provide an audible indication that the telephone set is

ringing, but it also may utilize lamps or the display as ringing indicators that provide a visual indication that the telephone set is ringing (Figure 4-4). The ringing indicators may be built into the telephone set or may be connected to it remotely. For example, a telephone may have ringing indicators in the form of a large flashing light and bell mounted outdoors so that it can be seen and heard at a distance.

Figure 4-4 Ringing indicators

Ringers have the following attributes:

• Volume

A ringer's volume is the sound level at which the ringer's audible indicator will ring.

• Mode

A ringer's mode indicates what it is doing. It may be either ringing or not ringing.

• Pattern

Pattern refers to the cadence, frequency, and other properties of the sound generated by a ringer when it is ringing. The pattern is set by the telephone system to indicate the type of call that is being presented, or to indicate that a particular number was called. If it is being used to indicate the type of call, it is one of the following:

unspecified – meaning call type ringing is not supported internal – the call is from inside the telephone system external – the call is from outside the telephone system priority – the call has been marked as high priority

callback – the callback feature^4-6 has been used to place the call maintenance – the call is maintenance-related (e.g., a test) attendant – the call is from an attendant

transferred – the call is being transferred to the device

prompting – the telephone system is prompting^4-9 the device

• Count

A ringer's count is the number of ring cycles^4-7 that have been completed since the ringer began ringing. It is zero if the ringer's mode is not ringing.

A physical device element may have more than one ringer, but only one may be actively ringing at a time.

4-6 Call back feature — The call back feature is explained in Chapter 5, section 5.14.3. It involves a call from a device that was previously busy or unavailable.

4-7 Ring cycles — A ring cycle is the time between the playing of each ringer pattern while a device is ringing. The individual ringer pattern may be a simple on-off pattern or a more complex sequence. In any case, this attribute does not reflect the number or length of cycles within the pattern.