E.F. Johnson Company Summit DM 975x, Руководство по обслуживанию

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UNIVERSAL DIGITAL AND DATA INTERFACE
B-2
Revised May 1998
Part No. 001-9750-006
CAUTION: The DB25 universal interface connector is
a non-standard port. Therefore, do not connect any
equipment to this port not specially designed for this
interface because equipment damage may result.
Normally, there is no need to make internal modi-
fications to the transceiver because connection points
commonly used are available at the connector and
programmable internal gating circuits provide the
required routing of audio signals. The programming of
the universal interface functions is performed using
the same software used to program the transceiver as
described in Section 4. Universal interface program-
ming is described in Section 4.8.
Gating of the receive and transmit audio signals
in Figure 1 is programmable on a system by system
basis (each selectable system can be programmed for a
different configuration) and are also controllable
dynamically by the Serial Data Bus. The control func-
tions are programmable only on a radio-wide basis
(they are the same for all selectable systems and
groups). Refer to Sections B.3, B.4, and B.5 for more
information on the audio and control signals.
B.2 POWER SUPPLY
A description of the power supply lines is located
in Table 1. Since the Switched Battery and 8-volt
power sources used by the universal interface also
provide power to other accessories, the total power
consumption of all accessories must not exceed the
limits stated in Table 1. Other accessories which use
the universal interface power sources are as
follows:
•
Equipment connected to the remote interface (J402)
such as a remote control unit.
•
Internal accessories installed in the option slots such
as encryption or compandor modules.
B.3 RECEIVE AUDIO SIGNALS
B.3.1 PIN DESCRIPTIONS
Descriptions of the receive audio pins are located
in Table 2, and a block diagram showing how these
signals are internally routed to the receive audio
processing and gating circuitry is shown in Figure 2.
B.3.2 RECEIVE AUDIO GATING
The receive audio gating circuitry has been
designed to provide several choices for receive audio
routing (such as injecting before or after filtering and
de-emphasis). The receive audio routing for the
universal interface can be programmed for the four
modes shown in Table 3. Each mode enables and
disables the gates (indicated by “Mx”) so that the
audio output signal from the external equipment (indi-
cated by “Device x”) is routed to the desired filtering
circuit. These modes are programmed for each select-
able system as described in Section 4.8.3. The desired
mode can also be selected by data on the Serial Data
Bus (see Section B.8).
B.4 TRANSMIT AUDIO SIGNALS
B.4.1 PIN DESCRIPTIONS
Descriptions of the transmit audio pins are
located in Table 4, and a block diagram showing how
these signals are internally routed to the transmit audio
filtering and gating circuitry is shown in Figure 3.
B.4.2 TRANSMIT AUDIO PROGRAMMING
As with the receive audio circuitry, the transmit
audio circuitry has been designed to provide several
choices for routing (such as injecting before or after
bandpass the bandpass filter). The transmit audio
routing can be programmed for the four modes shown
in Table 5. These modes are programmed for each
selectable system as described in Section 4.8.3. The
desired mode can also be selected by data on the Serial
Data Bus (see Section B.8).
Table B-1 Power Supply Pin Description
Function Pin Description
Switched Battery 22 Standard battery voltage fused by 4-
ampere fuse F500 on the PA board.
Maximum source current is 300mA.
8 volts DC 23 Regulated 8-volt supply (±5%).
Maximum source current is 300mA.
Ground 19,
24
Radio chassis ground.