General Operational Capabilities - Motorola P Series Selling Manual

2-14
3.3.3 Audio Pre-emphasis and De-emphasis
The Audio Filter IC within the radio's circuitry performs RX and TX audio shaping (ie. Þltering,
ampliÞcation and attenuation) to improve overall audio quality and increase voice clarity.
Pre-emphasis is performed on transmission whereas de-emphasis is the complimentary process
performed on reception. The CPS allows the ßexibility of selecting pre-emphasis, de-emphasis, both
or neither on a per-personality basis.
3.4

General Operational Capabilities

3.4.1 Private Lineª Signalling
Motorola Private Lineª enables your customers to effectively manage their communications
resources by allowing different groups of radio users to share a common channel, without disrupting
each other's conversations.
In technical terms, Private Lineª (PL) is a "squelch code" that acts as a Þlter on the communication
channel - if PL is being used, only communications with the appropriate PL are heard;
communications with the wrong PL are Þltered out.
To fully understand the beneÞts of PL, imagine that one of your customers is a large Do-It-Yourself
(DIY) retail outlet:
After consulting with the customer you agree that the anticipated communications trafÞc can be
supported by a single channel system (i.e. transmit and receive frequency pair). However, the
workforce consists of several distinct groups of sales assistants working within the various different
store departments.
You decide to conÞgure the customer's radios to support several different PL codes, to differentiate
between the different departments. You conÞgure the radios with 4 different personalities, each
assigned to a different position on the rotary channel selector knob. To the end user, it appears that
the radio supports four distinct channels. In reality each ÒchannelÓ is a different personality using the
same frequency channel. This is shown in table 2-13:
The squelch on channel 2, for example, will only open when the "lighting" PL code is present.
This allows the staff working the Lighting department to use channel 2 without having their
concentration interrupted by communications from the other departments. Similarly, conversations
between the Lighting department staff will not disturb the other groups.
Table 2-13 Channel Examples
Channel
1 Plumbing
2 Lighting
3 Timber
4 Hardware
Department
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