Service Manual

SRM9000 SERIES SERVICE MANUAL

• If the Acknowledge property of a Decode Identity is set to 'Auto Interrogate' or

'Transpond & Auto Interrogate' then the Auto Interrogate encode identity is

transmitted.

Roaming This is a process that allows changing between regional trunking systems which

have different Operator Identities (OPID 's). Not allowed on MPT1343 Systems.

RSSI Received Signal Strength Indicator.

Scanning Process of switching between the channels in the nominated search group in

cyclic sequence, stopping when the search condition (which may be to look for

either a free or a busy channel) is satisfied.

SDM Short Data Message.

Search Group A group of channels that are either scanned for a signal above the search

threshold or are compared and voted for the strongest signal

Selcall Selective Calling - a system of signalling which allows 'dialling up' of specific

mobiles, portables and controllers. Such a system may be used to pass messages

as a data message to a specific user or group of users. It can be used to provide

remote switching facilities and to provide access control into community repeaters

or similar devices.

Selcall Mute A state of the audio gate whereby the loudspeaker is muted (closed).

Selcall System Selective Calling, uses a tone sequence at the start, and end, of a call to control

which members of a fleet react to the transmission.

SFM Short Form Memory.

Sidetone Sidetone is the audio which can be (optionally) heard when Selcall, DTMF and

toneburst transmissions are made.

Simplex Mode of operation whereby the radio operates as a conventional fixed channel

radio outside the Trunking network.

Squelch System used to prevent weak, unintelligible signals and random noise from being

heard by a radio operator while still allowing intelligible signals to be received

normally. This is accomplished by the use of a threshold below which any

received signals are ignored. Only signals whose signal-to-noise ratio is above the

squelch level cause the audio circuits of the radio to be enabled, with the result

that only satisfactory signals are received. The squelch level is specified in

SINAD.

Star (*) digits Digits known as Status or Message digits. These digits are used for three

purposes:

• Status Digits for Selcall Identities

• Wildcard digits in Status strings

• Use in DTMF dialled strings - their use is network dependent to access special

services.

Status A feature whereby a radio's status (or usually the status of the radio's user) can be

transmitted and a status message from other radios can be displayed. This

operates through status digits in Selcall identities. Either in Encode Identities or

Decode Identities as follows:

Encode Identities: Status digits within the identity are used to transmit the current

situation of the radio's user (e.g. "Out To Lunch").

Decode Identities: Status digits are looked up in a table (Status Menu) for possible

messages to display.