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new channel first select it with the channel selector switch ( 4 ) CHANNEL. Then
depress a memory key for 4 or 5 seconds until a second receipt tone indicates
the overwriting of the new channel number into the corresponding memory. To
call a saved channel depress briefly the corresponding memory key. On the left
side of the display the actual memory number is displayed in case of data stor-
age or recall. The memory number disappears by selecting a new channel.
11. DTMF SELECTIVE CALL SYSTEM [ CALL / SET ] :
General :
The DTMF selective call system ( = Dual Tone Modulation Frequency ) enables
the radio operator to open one or more muted receiver by transmitting a specially
coded tone sequence. This is only possible on condition that all partners use the
same channel, modulation mode and selective call system. The transceivers
must be switched on and operate normally and the selective call system has to
be set into standby mode to receive the coded tone calls. This will mute the re-
ceiver ( loudspeaker ) until the detection of a coded tone sequence, which corre-
sponds with the own reception code of the transceiver. This will open the re-
ceiver and it will remain unmuted even when the calling station stops transmit-
ting. So all activities on this channel can be heard, and those stations which are
not equipped with a selective call system, too. It is also possible to communicate
with them. They are only unable to open a receiver muted by a selective call sys-
tem.
The TEAM SelCom 4000 selective call system uses 4 dual tones in succession.
There are 4 different dual tones. So there are 256 combinations possible. The
reception code and the transmission code can be programmed separately from
each other. For individual call it is recommended for each participant to program
his own reception code. Example : 4 Partners, consisting of head office and 3
mobile stations: Head office = 1111 / Jack mobile = 1112 / Susan mobile = 1113
/ John mobile = 1114. In case of group call all members have the same reception
code. This will unmute all receivers if the transmitted code is sent out interfer-
ence-free and free of noise. In all cases the transmission code of the calling sta-
tion and the reception code of the listening station have to match. In our example
the head office has to change its transmission code to reach every participant in
case of individual call. The same applies to the mobile stations if they want to
reach each other. If the communication is made with the help of the head office all
mobile stations need only the transmission code 1111.
Entry of the reception code :
Depress briefly the button ( 7 ) SET so that the symbol "music note" appears in
the display on the top right of the channel number. The receiver is now muted.
Depress the key ( 7 ) SET again but hold it for 3 or 4 seconds until a second
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