Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
The present invention relates to a new and
improved construction of apparatus operating with pulse-code-
modulation or similar digitizing techniques and according to the
time-division multiplexing principle for processing the informa-
tion from a number of telephone channels, which apparatus is of
the type comprising a housing, at the front plate of which there
are arranged operating elements and possessing connections or
terminals for theinput of the information to be processed and
the output of the processed information.
SUMMARY OF THE INVENTION
It is a primary object of the present invention
to provide a new and improved construction of apparatus of the
previously mentioned type which enables utilization for different
fields of application without any structural changes.
Now in order to implement this object and others,
which will become more readily apparent as the description
proceeds, the apparatus of the present development is manifested
by the features that there are accommodated in the housing, apart
from the components associated conjointly with all of the tele-
phone channels, a group of components for each telephone channel
which, apart from containing the elements or components needed
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for the conversion of analogue signals into digital pulses and
digital pulses into analogue signals also contains call signal
converters and call signal transmitters, respectively. The
elements of each channel can be adjusted by means of an
associated operating element at the housing-front plate indepen-
dent of the group of components of the remaining channels to one
of a number of operating states, and for at least one of these
operating states the arriving digital pulses pass without change
through the related channel.
By virtue of the fact that the operating state of each
channel can be adjusted independently of the operating state of
the other channels, the apparatus can be employed in different
ways without dismantling or exchanging groups of components and
the components themselves.
In accordance with the present invention there is pro-
vided an apparatus operating with pulse-code-modulation or
similar digitizing techniques and according to the time-division
multiplexing principle for processing the information from a
number of telephone channels, comprising a housing having a
front plate; operating elements arranged at the front plate of
said housing; terminal means provided at the front plate of the
housing for the input of information to be processed and the
output of the processed information; said housing containing
components conjointly associated with all of the telephone
channels; said housing further containing a group of components
for each telephone channel which comprises elements for the
conversion of analogue signals into digital pulses and digital
pulses into analogue signals and call signal converter means and
call signal transmitter means; said group of components for
each channel being adjustable by means of an associated operat-
ing element provided at the front plate of the housing indepen-
dent of the group of components of the remaining channels to one
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of a number of operating states; and the arriving digital pulses
passing without change to a related channel for at least one of
said operating states.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects
other than those set forth above, will become apparent when
consideration is given to the following detailed description
thereof. Such description makes reference to the annexed drawings
wherein:
Figure 1 is a perspective view of an apparatus for pro-
cessing the information from a number of telephone channels;
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Figure 2 illustrates the apparatus of Figure 1 but
with the front plate removed to reveal internal structure;
Figure 3 is a perspective plan view of a terminal box
or cabinet which can be connected with the apparatus of Figure l;
and
Figure 4 schematically illustrates different fields of
application of the apparatus shown in Figure 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The apparatus depicted by way of example in Figures 1
and 2 processes the information from a number of telephone chan-
nels in conventional manner according to the pulse-code-modulation
technique or a similar digitizing technique and according to the
time-division multiplexing principle. All of the components or
elements, such as the elements 34 to 47 shown by way of example in
Figure 2, needed for the operation of the apparatus are accommo-
dated in a watertight housing 1, as will be explained more fully
in the following description. If the apparatus is employed at the
transmitter end of the system, then the arriving analogue signals,
in each channel are converted by means of an analogue-digital con-
verter according to the pulse-code-modulation or a similar
technique into digital pulses. The digital pulses of each channel
are grouped into a pulse train according to the time-division
multiplexing principle with the aid of a multiplexer, which pulse
train is then transmitted to the réceiver station or receiver end
of the system.
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At the receiver end the received pulse train is again
distributed at the individual channels with the aid of demulti-
plexer in the apparatus. In each channel the digital pulses are
converted by means of a digital-analogue converter again into
analogue signals which are then further processed. Circuitry
suitable for this purpose has been disclosed in the commonly
assigned Canadian application serial no. 292,997 filed December 13,
1977, entitled "Apparatus Working With Pulse-Code-Modulation Or
Similar Digitizing Techniques And According To The Time-Division-
Multiplexing Principle For Processing The Information Of A NumberOf Telephone Channels".
It is also possible to encipher the pulse train at the
transmitter end, prior to transmission, by means of an enciphering
device. At the receiver end it is then necessary to carry out
deciphering in a deciphering device, before the pulse train is
delivered to the processing apparatus.
As will be apparent from the showing of Figures 1 and 2,
the apparatus housing comprises a housing box or casing 2 at which
there is attached a front plate 3. In the housing casing 2 there
are accommodated the components or elements 34 to 47 needed for
desired signal processing purposes, whereas at tha front plate 3
there are arranged the operating elements, connections or termi-
nals and indicator or display lamps.
The front plate 3 has an operating or control panel 4
having a number of operating or ~ctuation elements 5-15, each
coacting with schematically illustrated, not particularly
referenced
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scale. This operating panel ~ can be covered by means of a cover
member 16, as illustrated in Figure 2. The operating or control
elements 5-15 can be actuated by means of a not particularly
illustrated key which is attached to the cover member 16. By
means of the operating elements 5-12, each of which is associated
with a telephone channel, it is possible to adjust or set in each
channel, independent of the other channels, one of a number of
operating states or conditions, as will be described more fully
hereinafter. Since the illustrated apparatus is designed for a
maximum of 8 telephone channels, there are provided 8 operating
elements 5-12.
By means of the operating element 13 it is
possible to adjust or set the number of the apparatus or device.
This is of importance if a number of such apparatuses are
connected together and each apparatus or device is associated
with a different order number. If there is only used one
apparatus or device, then the operating element 13 is adjusted
to the number 1.
Of the 8 maximum possible channels it is also
possible to only use a part thereof, for instance ~ channels.
With the operating element 1~ it is possible to adjust the number
of channels with which the apparatus has been equipped.
The operating element allows for an adjustment or
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setting of the bit rate per channel. With the illustrated
apparatus the bit rate per channel can be set to, for instance,
16 ~ bits/s, 32 k bit/s, or 64 k bit/s.
Reference characters 17-22 designate different control
lamps.
Furthermore, there are arranged at the front plate 3
the schematically illustrated connections or terminals 23-28
serving for the connection of cables.
¦ At the terminal 23 there is connected the terminal box
¦ shown in Figure 3. ~y means of this te~minal 23 there is accom-
plished the input of the analogue signals received from the
telephone lines and the output of the analogue signals to the
telephone lines.
If a number of apparatuses or devices are connected
together, then the terminal 24 of the one device is connected with
the terminal 25 of the next following device by means of a cable.
A direct-current voltage source is connected with the
~¦ terminal 26, whereas the terminal 27 serves for connecting an
¦ alternating-current voltage source. A buzzer or equivalent
¦¦ structure can be connected with the terminal 28.
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By means or the switch 29 both of the voltage sources
are cut-in or cut-off. The lamp 30 illuminates when the ~o7tage
sources are turned-on. Further, there are provided two fuses 31
and 32 for the direct-current voltage source and the alternating-
current voltage source.
The components of the front plate are connected by flat
band cable 33 with the components or elements accommodated in the
housing casing 2 (Figure 2).
In this housing casing 2 there are accommoda~ed, on the !
one hand, all of the components which are conjointly associated
with all of the channels, and, on the other hand, the components
for each channel. As to these components or elements conjoin~ly
associated with all of the channels, in Figure 2 there have been
illustrated a supply current transducer 34 for direct-current and !
alternating-current operation, an alternating-current generator
35 for alternating-current voltage call, a synchronization circuit
36 for receiver operation, a clock generator 37 for receiver
operation, a base cycle oscillator 38 and a clock generator 39 for
transmitter operation.
These components or elements 35-39 are plug-in prin~ed
circuit boards which, when necessary, can be easily exchanged.
Each channel is associated with a single group of
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components ox assembly 40-~7, which li]iewise is constructed as an ¦
exchangeable prin~ed circuit boa~d. Each of these group of compo- I
nents or assem~ly 40-47 contains all of the elements or compo- ¦
nents, for instance, analogue~-digital converter and digital-
analogue converter, which are needed for the conversion of the
analogue signals into digital signals and digital signals into
analogue signals. Each group of components 40-47 is connected with
one of the operating elements 5-12 arranged a~ the front plate 3
so that by means of the associated operating element the operating
state in each channel can be adjusted. Each group of components
40-47 additionally possesses call signal converters and call
signal transmitters.
In the event that not all of the channels are needed,
then the group of components 40-47 of the not required channels
can be removed.
As already mentioned, the apparatus is connected both
at an alternating-current voltage source and also at a
direct-current voltage source. Normally, the apparatus operates
with alternating-current. Now if the alternating-current voltage
falls below a certain lower boundary or threshold value, then
there automatically is accomplished in the apparatus switch-over
to t-he direct-current mode of operation. As soon as the
alternating-current voltage again ascends to a value which is
a~ove the 10~.7er threshold value, then the apparatus is
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automatically agaiIl switched to the alternating-current mode of
operation.
In Figure 3 there is shown a simple terminal box 48
with ground terrllinal 48a, which, as previously mentioned, can
be connected by means of a cable 49 to the terminal 23 at the
front plate 3 of the apparatus. The terminal box 48 contains for
each channel a terminal board or block 50 at which there is
connPcted the telephone lines leading to the telephone stations.
The above-discussed structuring of the apparatus
enables connecting the telephone lines hy means of the simple
terminal box 48, shown in Figure 3, to the apparatus.
Now in Figure 4 there have been schematically shown
different possible fields of use or application of the devices
Sla, 51b, 51c and 51d in accordance with the equipment of Figures
1 and 2. The transmission between the individual devices or
apparatus of the network shown in Figure 4 is accomplished by
means of microwave or similar transmitting paths.
Based upon the possible fields of application the
previously discussed possible operating modes of the individual
channels will now be explained:
Operating condition 1 is set by connectln~ a
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¦~ transmission unit tor four-wire operation and external direct- ¦
current call. In ~igure 4 there is not shown any connection G~
such transmission unit.
Operating condition 2 is adjusted or set by connection
with the public telephone network operating in a two-wire mode of
operation, as the same has been illustrated in Figure 4 by the
telephone exchange station or location 53. With the operating
condition or state 2 the device 51 receives alternating-current
call signals and delivers direct-current call signals.
Operating state 3 is selected if a telephone apparatus
54 for central battery system is connected with the device 51.
The incoming direct-current call is converted in the device into
an alternating-current call.
Operating condition 4 is set by connecting a field
telephone 55 operating in a two-wire operating mode, each of
which field telephone 55 possesses a generator which can be
loperated by a hand crank 55a. The device 51 receives an alter-
¦nating-current call and transmits an alternating-current call. I
¦the operating state 4 it is also possible to connect a teieprinter
56 with the device 51. There is connected between the teleprinter
156 and the device 51 a "tone keyer" 57 which, depending upon the
¦Inature of the binary signals produced by the teleprinter 56,
leither does or does not generate a tone or sound.
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In the operating condition 5 the incorning digital
signals trave] without change through the related channel to the
output of the device. This is of advantage if the digi,tal
information is not processed at a node point of the device 51,
rather only must be further transmitted. There can be avoided an
unnecessary digital-analogue and analogue-digital conversion which;
is associated with losses. This operating condition 5 can be set
at the device 51a of Figure 4 if in one or a number of channels
the digital information received by the device 51c must be
further transmitted to the device 51b or the device 51d.
The call signals are converted in each channel into
digital pulses and again converted at the receiver end of the
system into analogue si,gnals. Therefore there are not required
any additional components for the processing of the call signa's.
With the described apparatus a]l of the componen-ts
or elements needed for processing the information are housed in a ¦
watertight housing 1. Therefore, it is not necessary to initially
assemble together different components of ihe equipment before
placing the same into operation.
Since the operating state of each channel can be
set by means o the operat,ing eleMents 5-]2 independent of the
operating state of the other channels, the apparatus can be
employed for different fields or use or application, without the
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groups of components having to be exchanged.
While there are shown and described present prefer-
red embodiments of the invention, it is to be distinctly under-
stood that the invention is not limited thereto, but may be
otherwise variously embodied and practiced within the scope of
the following claims. ACCORDINGLY,
