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Theory of Operation 2-35
Q0841 is switched on causing a low at
IJP
port
PA
1.
When the HOOK switch is closed, signal HOOK
is pulled
to
ground level. This switches off R0841 and the resulting high level at
IJP
port
PA
1 informs
the
IJP
about the closed hang up switch. The
IJP
informs the host radio about any status change on
the
HOOK line via SBEP bus.
2.1
0.9 Speaker
The control head contains a speaker for the receiver audio. The receiver audio signal from the
differential audio output
of
the audio amplifier located on the radio's controller is fed via connector
J0801-10,
-11
to the speaker connector P0801, pins 1 and
2.
The speaker
is
connected to the
speaker connector
P0801. The control head speaker can only be disconnected if an external
speaker, connected on the accessory connector,
is
used.
2.1
0.10 Electrostatic Transient Protection
2.11
Electrostatic transient protection
is
provided for sensitive components in the control head by diodes
VR0811 VR00812 and
VR0816-
VR0817. The diodes limit any transient voltages. The associated
capacitors provide radio frequency interference
(RFI) protection.
PassPort Trunking Controller Board (PTCB)
PassPort is an enhanced trunking protocol developed
by
Trident Microsystems that supports wide
area dispatch networking. A network is formed by
linking several trunked sites together
to
form a
single system. This offers users an extended communication coverage area. Additionally, users with
PassPort can seamlessly roam among all sites within the network. Seamless roaming means that
the radio user does not have
to
manually change the position on the radio when roaming from site-
to-site. For
models which feature PassPort Trunking operation, the PassPort Trunking Controller
Board
is
added to the top cover of the radio. This board also provides advanced voice storage
features. Refer to Figures 2-2, 2-3, and 2-5 for connector and
signal routing from and to the radio
and
PTCB. The PTCB is a non-servicable board and should be replaced
if
defective. The schematic
and circuit board
details are included in this manual for informational purposes only.
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