CA1191212A - Universal telephone ringing generator - Google Patents
Universal telephone ringing generatorInfo
- Publication number
- CA1191212A CA1191212A CA000442858A CA442858A CA1191212A CA 1191212 A CA1191212 A CA 1191212A CA 000442858 A CA000442858 A CA 000442858A CA 442858 A CA442858 A CA 442858A CA 1191212 A CA1191212 A CA 1191212A
- Authority
- CA
- Canada
- Prior art keywords
- signal
- binary word
- gated
- high level
- cadence
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M19/00—Current supply arrangements for telephone systems
- H04M19/02—Current supply arrangements for telephone systems providing ringing current or supervisory tones, e.g. dialling tone or busy tone
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Devices For Supply Of Signal Current (AREA)
Abstract
UNIVERSAL TELEPHONE RINGING GENERATOR
Abstract of the Disclosure A high level signal generator provides a wide range of ringing signals in response to a periodic clock signal and as addressed by d plurality of manually setable binary words. The binary words are gated one after the other from a corresponding plurality of binary word sources in response to a control signal. An analog signal source generates an analog signal with a frequency as selected by an instant gated binary word. A control signal generator generates the control signal having a plurality of states, each corresponding to d one of a corresponding plurality of cadence phases. Each of the cadence phases is of a duration consistent with an occurrence of a plurality of the clock signals as defined by the gated binary word.
-i-
Abstract of the Disclosure A high level signal generator provides a wide range of ringing signals in response to a periodic clock signal and as addressed by d plurality of manually setable binary words. The binary words are gated one after the other from a corresponding plurality of binary word sources in response to a control signal. An analog signal source generates an analog signal with a frequency as selected by an instant gated binary word. A control signal generator generates the control signal having a plurality of states, each corresponding to d one of a corresponding plurality of cadence phases. Each of the cadence phases is of a duration consistent with an occurrence of a plurality of the clock signals as defined by the gated binary word.
-i-
Description
Field of the Invention -The invention is in the Field of high level signal sources for telephony subscriber loop signalling and more particularly relates to a programmable ringing siynal generator.
Background of the Invention High level signalling requirements in any one typical tel-ephone switching facility usually fall into one main category being defined by frequency and cadence. A majority of telephone switching facilities in North America require a ringing signal frequency of 20 Hz and a cadence of 2 seconds of ringing followed by ~ seconds of silence.
However other standards o-f ringing frequencies and cadence may be required by an operating telephone company. For example in North America, frequencies in a range of 16 and 66 2/3 Hz are standard in either of two cadences used by operating telephone companies. Various high level signalling standards prevail in telephone operating companies of various other countries.
One arrangement for meeting the high level signalling requirements is to provide at least one separate ringing generator for each ringing frequency required in a telephone switching facility. This however causes a proliferation of equipment codes, increased manuFacture, and operating company inventory and consequent expense. One solution to this problem is disclosed in Canadian Patent No. 1,118,922 issued on 23 February, 1982 to R. Hayward, J. Bottrill and myself entitled: "Universal Signal Generator for Generating Telephone System High Level Signals".
This signal generator is capable of generating a wide variety of ringing and test signals in accordance with internally stored data. A portion of
Background of the Invention High level signalling requirements in any one typical tel-ephone switching facility usually fall into one main category being defined by frequency and cadence. A majority of telephone switching facilities in North America require a ringing signal frequency of 20 Hz and a cadence of 2 seconds of ringing followed by ~ seconds of silence.
However other standards o-f ringing frequencies and cadence may be required by an operating telephone company. For example in North America, frequencies in a range of 16 and 66 2/3 Hz are standard in either of two cadences used by operating telephone companies. Various high level signalling standards prevail in telephone operating companies of various other countries.
One arrangement for meeting the high level signalling requirements is to provide at least one separate ringing generator for each ringing frequency required in a telephone switching facility. This however causes a proliferation of equipment codes, increased manuFacture, and operating company inventory and consequent expense. One solution to this problem is disclosed in Canadian Patent No. 1,118,922 issued on 23 February, 1982 to R. Hayward, J. Bottrill and myself entitled: "Universal Signal Generator for Generating Telephone System High Level Signals".
This signal generator is capable of generating a wide variety of ringing and test signals in accordance with internally stored data. A portion of
2~2 the stored data is periodically selected From time to time by a processor, usually a call processor in the telephone switching facility~ to control the signal output of the signal generator. This arrangement has been found to be quite satisfactory in smaller telephone switching facilities.
However, in larger switching facilities it has been observed that as a larger number of the signal generators are required a correspondingly increased amount of processor time is also required for operating the signal generators.
Summary of the Invention It is an object of the present invention to provide a f'lexible high level signal generator suitable -for use in telephone switching facilities, but which is controllable independent of' a call processor or the like in the telephone switching Facility.
A p'lurality of the high level signal generators is particularly useful in a larger -telephone switching facility. Upon installation of an individual high level signal generator, switch settings effected by the installer define a frequency signal which is generated in each of four sequential phases in either oF two standard cadences.
Subsequently, information as to the physical location of the generator and installer defined signal generation functions, is manually entered into the common control data base of the telephone switchirlg f'acility such that output signals from the high level signal generator are directable by a call processor in the switching facility to various subscriber loops as required. Hence in the larger telephone switching facility some high level signal generators are typically dedicated to supplying the higher power requirement oF the most popular ringing signal frequency, for example 20 Hz while individual ones of the high level signal generator are used to supply up to four different ringing signal frequencies across the four phases of either of two cadence standards.
In accordance with the invention a high level signal generator being operable by periodic clock signals includes a plurality of manually se~able binary word sources corresponding in number to a plurality of cadence phases. Each of the binary word sources provides a binary word for defining a frequency address and a cadence phase period.
The binary words are gated one at a time from the binary word sources via a gating means which is responsive to a control signal. An analocJ signal source is responsive to the periodic clock signals for generating an analog signal having a frequency as selected by the instan-t gated binary word. A contr()l signal generating means generates the control signal with a plurality of states. Each state corresponds to one of the cadence phases and is of a duration consistent with an occurrence of a plurality of the clock signals as defined by the gated binary word.
Description of an Example Embodiment An example embodiment is described with reference to the ; accompanying drawing which is a block schematic drawing of a high level 2() signal generator in accordance with the invention.
Referring to the drawing an analog signal generator 10 produces a high level analog signal at an output lead 11 for direct application to subscriber lines and the like associated with a telephone switching system not shown. The analog signal generator 10 may be provided in the general form of that illustrated in figure 2 of the previously mentioned patent. Alternately it may generally consist of a counter addressed memory similar to the arrangement of the figure 2. The output of the rrlemory is connected to a digital-to-analog converter for converting output data from the memory to an analog signal which in turn is used to drive a high power amplifier, the output of which appears on the lead 11. The analog signal generator is responsive in operation to frequency address signals from a translation read-only-memory (ROM) 13 and an 8 kH~ clock signal from a source 14.
In this example frequency and cadence of the high level signal is defined by manually setable binary words, four of which are provided by means of four corresponding banks of switches S~, S1, S2 and S3. Each bank of swiches is identical to the other. In each bank of switches each of seven switches SW1 - SW7, is connected between ground and a corresponding lead of a binary word bus B0 - B3 and each of seven corresponding resistors are connected between a voltage -~V and the corresponding lead of the corresponding binary word bus. The settings of the switches in each bank define the operating requirements of the high level signal generator as for example is illustrated in the following tables.
Table A illustra-tes switch settings of the switches SW4 -SW7 and the corresponding North American standard frequencies. Thesetting of the switches SW3 and SW2 are usecl to select one of three power output levels.
TABLE A
SWITCH SETTING
Frequency Power in Hertz SW7 SW6 SW5 SW4 SW3 SW2 Output O O Low ~ 0 1 Medium lo 40 0 1 1 1 ¦ 1 0 High 5~ 1 0 1 0 Table B illustrates two ~orth American cadence standards being selectable by switch SWlo Each cadence includes four phases 0 - 3;
the period of each phase being indicated in seconds in table B.
TABLE B
_ STANUARD SWITCHCADENCE PHASE
SWl- - o _ 1 2 _ ~ ___ Bell 0 2 2 2 2 ~ _ . _ _. .
REA 1 1.95 1.35 1.35 1.35 L~
Different frequencies and/or cadences for example corresponding to European standards are of course available by substituting new information in the ROM 13 and in the ROM in the analog signal generator 10.
In operation at any instant one of the four defined binary words is selected by a multiplexer 12 in accordance with control signals supplied thereto via control leads 22. The selected binary word is gated by the multiplexer 12 to an address port of the ROM 13. The control leads 22 are also connected to the address port of the ROM 13. The ROM 13 is used to translate the binary words of the switch settings in combination with the control signals, to a more convenient address for use in the analog signal generator 10 For frequency and power level selection. A
portion of the address is also used by a phase counter 15 to clefine the period of the instant phase of the cadence. In the phase counter 15, eight bits of the address define a start value for counting of the clock siynal froln the clock source 14. The phase counter 15 counts from the instant set value at the beginning of the instant phase period until it is full at which time a carry signal is asserted at its output. The carry signal assertion signifies an end of the instant phase period. A two bit counter 1~ is incremented by the carry signal assertion which immediately causes another binary word to be gated to the ROM 13. The carry signal remains asserted until the translated value of this binary word is accepted by the phase period counter 15, at which time the next phase period begins. This operation continues such that the four phases of one oF the two cadence standards in the table 3 and 1 to 4 of the frequencies at 1 to 3 of the power levels in the table A are sequentially available, one following another, at the output 11.
However, in larger switching facilities it has been observed that as a larger number of the signal generators are required a correspondingly increased amount of processor time is also required for operating the signal generators.
Summary of the Invention It is an object of the present invention to provide a f'lexible high level signal generator suitable -for use in telephone switching facilities, but which is controllable independent of' a call processor or the like in the telephone switching Facility.
A p'lurality of the high level signal generators is particularly useful in a larger -telephone switching facility. Upon installation of an individual high level signal generator, switch settings effected by the installer define a frequency signal which is generated in each of four sequential phases in either oF two standard cadences.
Subsequently, information as to the physical location of the generator and installer defined signal generation functions, is manually entered into the common control data base of the telephone switchirlg f'acility such that output signals from the high level signal generator are directable by a call processor in the switching facility to various subscriber loops as required. Hence in the larger telephone switching facility some high level signal generators are typically dedicated to supplying the higher power requirement oF the most popular ringing signal frequency, for example 20 Hz while individual ones of the high level signal generator are used to supply up to four different ringing signal frequencies across the four phases of either of two cadence standards.
In accordance with the invention a high level signal generator being operable by periodic clock signals includes a plurality of manually se~able binary word sources corresponding in number to a plurality of cadence phases. Each of the binary word sources provides a binary word for defining a frequency address and a cadence phase period.
The binary words are gated one at a time from the binary word sources via a gating means which is responsive to a control signal. An analocJ signal source is responsive to the periodic clock signals for generating an analog signal having a frequency as selected by the instan-t gated binary word. A contr()l signal generating means generates the control signal with a plurality of states. Each state corresponds to one of the cadence phases and is of a duration consistent with an occurrence of a plurality of the clock signals as defined by the gated binary word.
Description of an Example Embodiment An example embodiment is described with reference to the ; accompanying drawing which is a block schematic drawing of a high level 2() signal generator in accordance with the invention.
Referring to the drawing an analog signal generator 10 produces a high level analog signal at an output lead 11 for direct application to subscriber lines and the like associated with a telephone switching system not shown. The analog signal generator 10 may be provided in the general form of that illustrated in figure 2 of the previously mentioned patent. Alternately it may generally consist of a counter addressed memory similar to the arrangement of the figure 2. The output of the rrlemory is connected to a digital-to-analog converter for converting output data from the memory to an analog signal which in turn is used to drive a high power amplifier, the output of which appears on the lead 11. The analog signal generator is responsive in operation to frequency address signals from a translation read-only-memory (ROM) 13 and an 8 kH~ clock signal from a source 14.
In this example frequency and cadence of the high level signal is defined by manually setable binary words, four of which are provided by means of four corresponding banks of switches S~, S1, S2 and S3. Each bank of swiches is identical to the other. In each bank of switches each of seven switches SW1 - SW7, is connected between ground and a corresponding lead of a binary word bus B0 - B3 and each of seven corresponding resistors are connected between a voltage -~V and the corresponding lead of the corresponding binary word bus. The settings of the switches in each bank define the operating requirements of the high level signal generator as for example is illustrated in the following tables.
Table A illustra-tes switch settings of the switches SW4 -SW7 and the corresponding North American standard frequencies. Thesetting of the switches SW3 and SW2 are usecl to select one of three power output levels.
TABLE A
SWITCH SETTING
Frequency Power in Hertz SW7 SW6 SW5 SW4 SW3 SW2 Output O O Low ~ 0 1 Medium lo 40 0 1 1 1 ¦ 1 0 High 5~ 1 0 1 0 Table B illustrates two ~orth American cadence standards being selectable by switch SWlo Each cadence includes four phases 0 - 3;
the period of each phase being indicated in seconds in table B.
TABLE B
_ STANUARD SWITCHCADENCE PHASE
SWl- - o _ 1 2 _ ~ ___ Bell 0 2 2 2 2 ~ _ . _ _. .
REA 1 1.95 1.35 1.35 1.35 L~
Different frequencies and/or cadences for example corresponding to European standards are of course available by substituting new information in the ROM 13 and in the ROM in the analog signal generator 10.
In operation at any instant one of the four defined binary words is selected by a multiplexer 12 in accordance with control signals supplied thereto via control leads 22. The selected binary word is gated by the multiplexer 12 to an address port of the ROM 13. The control leads 22 are also connected to the address port of the ROM 13. The ROM 13 is used to translate the binary words of the switch settings in combination with the control signals, to a more convenient address for use in the analog signal generator 10 For frequency and power level selection. A
portion of the address is also used by a phase counter 15 to clefine the period of the instant phase of the cadence. In the phase counter 15, eight bits of the address define a start value for counting of the clock siynal froln the clock source 14. The phase counter 15 counts from the instant set value at the beginning of the instant phase period until it is full at which time a carry signal is asserted at its output. The carry signal assertion signifies an end of the instant phase period. A two bit counter 1~ is incremented by the carry signal assertion which immediately causes another binary word to be gated to the ROM 13. The carry signal remains asserted until the translated value of this binary word is accepted by the phase period counter 15, at which time the next phase period begins. This operation continues such that the four phases of one oF the two cadence standards in the table 3 and 1 to 4 of the frequencies at 1 to 3 of the power levels in the table A are sequentially available, one following another, at the output 11.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A high level signal generator being operable in response to periodic clock signals, comprising:
a plurality of manually setable binary word sources corresponding in number to a plurality of cadence phases, each of the binary word sources being for providing a binary word for defining a frequency address and a cadence phase period;
means for gating the binary words one at a time from the binary word source in response to a control signal;
an analog signal source being responsive to the clock signals for generating an analog signal having a frequency as selected by the instant gated binary word; and means for generating the control signal having a plurality of signal states, each signal state corresponding to one of the cadence phases and each signal state persisting for a duration consistent with an occurrence of a plurality of the clock signals as defined by the gated binary word.
a plurality of manually setable binary word sources corresponding in number to a plurality of cadence phases, each of the binary word sources being for providing a binary word for defining a frequency address and a cadence phase period;
means for gating the binary words one at a time from the binary word source in response to a control signal;
an analog signal source being responsive to the clock signals for generating an analog signal having a frequency as selected by the instant gated binary word; and means for generating the control signal having a plurality of signal states, each signal state corresponding to one of the cadence phases and each signal state persisting for a duration consistent with an occurrence of a plurality of the clock signals as defined by the gated binary word.
2. A high level signal generator as defined in claim 1 wherein the control signal generating means comprises:
a first counter for generating a carry signal with each full count of the periodic clock signals and in response to the carry signal initiating a new count from a starting number as defined by a newly gated binary word; and a second counter for generating the control signal in response to the carry signal.
a first counter for generating a carry signal with each full count of the periodic clock signals and in response to the carry signal initiating a new count from a starting number as defined by a newly gated binary word; and a second counter for generating the control signal in response to the carry signal.
3. A high level signal generator as defined in claim 1 further comprising:
a translator means being connected in series with an output of the gating means for converting the gated binary word from a form consistent with conveniences of manual setting to a form consistent with operation of the analog signal source.
a translator means being connected in series with an output of the gating means for converting the gated binary word from a form consistent with conveniences of manual setting to a form consistent with operation of the analog signal source.
4. A high level signal generator as defined in claim 2 further comprising:
a translation read-only-memory (ROM) having an address port connected to receive the gated binary word and the control signal, and a data port connected to the first counter, the translation ROM having conversion data stored therein consistent with conveniences of operation of the first counter and the analog signal source.
a translation read-only-memory (ROM) having an address port connected to receive the gated binary word and the control signal, and a data port connected to the first counter, the translation ROM having conversion data stored therein consistent with conveniences of operation of the first counter and the analog signal source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000442858A CA1191212A (en) | 1983-12-08 | 1983-12-08 | Universal telephone ringing generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000442858A CA1191212A (en) | 1983-12-08 | 1983-12-08 | Universal telephone ringing generator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1191212A true CA1191212A (en) | 1985-07-30 |
Family
ID=4126698
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000442858A Expired CA1191212A (en) | 1983-12-08 | 1983-12-08 | Universal telephone ringing generator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1191212A (en) |
-
1983
- 1983-12-08 CA CA000442858A patent/CA1191212A/en not_active Expired
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Legal Events
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| MKEC | Expiry (correction) | ||
| MKEX | Expiry |