CA2058536A1 - Radio pager tone alarm circuit for generating variable duty constant audio frequency pulses modulated with unique tone pattern - Google Patents
Radio pager tone alarm circuit for generating variable duty constant audio frequency pulses modulated with unique tone patternInfo
- Publication number
- CA2058536A1 CA2058536A1 CA002058536A CA2058536A CA2058536A1 CA 2058536 A1 CA2058536 A1 CA 2058536A1 CA 002058536 A CA002058536 A CA 002058536A CA 2058536 A CA2058536 A CA 2058536A CA 2058536 A1 CA2058536 A1 CA 2058536A1
- Authority
- CA
- Canada
- Prior art keywords
- pulses
- frequency
- generating
- clock
- audio
- 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.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B3/00—Audible signalling systems; Audible personal calling systems
- G08B3/10—Audible signalling systems; Audible personal calling systems using electric transmission; using electromagnetic transmission
- G08B3/1008—Personal calling arrangements or devices, i.e. paging systems
- G08B3/1016—Personal calling arrangements or devices, i.e. paging systems using wireless transmission
- G08B3/1025—Paging receivers with audible signalling details
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
"Radio Pager Tone Alarm Circuit For Generating Variable Duty Constant Audio Frequency Pulses Modulated With Unique Tone Pattern"
ABSTRACT OF THE DISCLOSURE
In a radio pager, a paging signal containing the pager's own identifier and a particular alert tone pattern is received. On receiving this signal, constant audio-frequency pulses having a duty ratio increasing as a function of time are generated and modulated with the alert tone pattern.
The modulated pulses are applied to a loudspeaker for alerting the user with an escalating alert sound.
ABSTRACT OF THE DISCLOSURE
In a radio pager, a paging signal containing the pager's own identifier and a particular alert tone pattern is received. On receiving this signal, constant audio-frequency pulses having a duty ratio increasing as a function of time are generated and modulated with the alert tone pattern.
The modulated pulses are applied to a loudspeaker for alerting the user with an escalating alert sound.
Description
TITLE OF THE INVENTION
2"Radio Pager Tone Alarm Circuit For Generating Variable Duty Constant 3Audio Frequency Pulses Modulated With Unique Tone Pattern"
sThe present invention relates generally to radio pagers, and more 6specifically to a sound alarm circuit for such radio pagers which generates 7an alert tone of escalating sound levels.
8A radio pager having the capability of successively escalating the gsound level of an alert tone is described in Japanese Patent Publication 63-10252030 (Tokkaisho). According to the prior art technique, constant audio 11 frequency pulses are modulated with a variable duty tone pattern that 12 identifies particular incoming pages. The duty ratio of the tone pattern is 13 successively increased to increase the sound level of the tone.
14 One serious disadvantage of the prior art technique is that since the , 15 sound level is controlled by the duty ratio of a tone pattern, the alert tone ~ 16 patterns as standardized by the Post Office Code Standardization `i 17 Advisory Group (POCSAG) cannot be employed for escalating alert tones.
19 It is therefore an object of the present invention to provide a radio 20 pager that enables internationally standardized alert tone patterns to be 21 employed for alerting users with an escalating sound level.
22 According to the present invention, the radio pager comprises a 23 receiver for receiving a paging signal containing a unique identifier 24 identifying the own radio pager and an alert tone pattern. A pulse 2S generating clrcuit generates audio-frequency pulses having a duty ratio 2 6 increasing as a function of time in response to receipt of the paging signal.
: 27 A modulating means is provided for modulating the variable duty pulses 2 8 with the alert tone pattern for applying the modulated pulses to a ~.1 2 9 loudspeaker.
, , . ;
, . . .. .
:~ . - , -, , . . , - - , . . .
BRIEF DESCR!PTION OF THE DRAWINGS
2 The present invention will be described in further detail with reference 3 to the accompanying drawings, in which:
sThe present invention relates generally to radio pagers, and more 6specifically to a sound alarm circuit for such radio pagers which generates 7an alert tone of escalating sound levels.
8A radio pager having the capability of successively escalating the gsound level of an alert tone is described in Japanese Patent Publication 63-10252030 (Tokkaisho). According to the prior art technique, constant audio 11 frequency pulses are modulated with a variable duty tone pattern that 12 identifies particular incoming pages. The duty ratio of the tone pattern is 13 successively increased to increase the sound level of the tone.
14 One serious disadvantage of the prior art technique is that since the , 15 sound level is controlled by the duty ratio of a tone pattern, the alert tone ~ 16 patterns as standardized by the Post Office Code Standardization `i 17 Advisory Group (POCSAG) cannot be employed for escalating alert tones.
19 It is therefore an object of the present invention to provide a radio 20 pager that enables internationally standardized alert tone patterns to be 21 employed for alerting users with an escalating sound level.
22 According to the present invention, the radio pager comprises a 23 receiver for receiving a paging signal containing a unique identifier 24 identifying the own radio pager and an alert tone pattern. A pulse 2S generating clrcuit generates audio-frequency pulses having a duty ratio 2 6 increasing as a function of time in response to receipt of the paging signal.
: 27 A modulating means is provided for modulating the variable duty pulses 2 8 with the alert tone pattern for applying the modulated pulses to a ~.1 2 9 loudspeaker.
, , . ;
, . . .. .
:~ . - , -, , . . , - - , . . .
BRIEF DESCR!PTION OF THE DRAWINGS
2 The present invention will be described in further detail with reference 3 to the accompanying drawings, in which:
4 Fig. 1 is a block diagram of a radio pager of the present invention;
s Fig. 2 is a block diagram of a sound alarm circuit of this invention;
6 Fig. 3 is a waveform diagram associated with the sound alarm circuit 7 of Fig. 2;
8 Fig. 4 is a waveform diagram of the tone pulses modulated with a 9 POCSAG A-code tone pattern;
Fig. 5 is a block diagram of a modified form of the sound alarm 1 1 circuit;
12 Fig. 6 is a waveform diagram associated with the sound alarm circuit 13 of Fig. 5;
14 Fig. 7 is a block diagram of an alternative form of the sound alarm circuit; and 16 Fig. 8 is a waveform diagram associated with the sound alarm circuit 17 of Fig. 7.
19 A radio pager of the present invention as represented in Fig. 1 20 comprises a front end 2 for converting paging signals received by antenna 21 1 to baseband signals for coupling to a waveshaper 3. The output of 22 waveshaper 3 is applied to a decoder 4 in which the received signal is 23 checked for a coincidence between a pager identifier contained in it and 24 the one stored in a PROM (programmable read only memory) 5. On 2 5 detecting a coincidence, decoder 4 alerts a sound alarm circuit 6 with a 26 POCSAG (Post Office Code Standardization Advisory Group) alert tone 27 signal having one of predetermined tone patterns or cadences. For 28 example, one such cadence is a cyclic sequence of 7/8-second ~N and 29 1/8-second OFF. Sound alarm circuit 6 modulates the tone signal with a (l , ~:
. . . . . ..
... . . ~ ; .
- . . .
- : . .. : ,. .-. . - --, , ' , . ....
variable duty pulse sequence and activates a loudspeaker 7. A reset 2 switch 8 is connected to the decoder 4 to be operated when the user 3 answers an incoming page.
4 As shown in Fig. 2, sound aiarm clrcuit 6 comprises an AND gate 10 s that is responsive to an enable signal from decoder 4 to pass high-6 frequency clock pulses from a clock source 9 to frequency dividers 11 and 7 12, and further to an up-counter 13 during the time the pager is being 8 alerted. As shown in Fig. 3, frequency divider 11 divides the frequency of 9 the clock to produce an output whose frequency determines the pitch of the alert tone, typically at 2.6 kHz, and frequency divider 12 divides that 11 clock frequency so that its output determines the rate at which the duty 12 ratio of the 2.6-kHz pulse sequence is varied. Typicatly, the duty ratio is 13 stepwisely varied at 6-second intervals. The output of frequency divider 14 11 is applied to the up-counter 13 as a reset pulse so that its output 15 represents a digital count value which continuously increments in response 16 to the clock pulse until it rapidly drops to zero in response to the reset 17 pulse. On the other hand, the output of frequency divider 12 is applied to 18 a down-counter 15 to produce a decremental binary count value which 19 represents the varying rate of the duty ratio. A monostable multivibrator 2 0 14 iS provided for producing a pulse for clearing the contents of down-21 counter 15 as soon as the pager is alerted.
22 The digital output of down~counter 15 is applied to a binary-to-duty 2 3 converter 16 which converts it to a digital value representing the duty ratio 24 of the 2.6-kHz pulse sequence for each 6-second interval. In a typical 25 example, binary-to-duty converter 16 successively generates outputs 2 6 representing duty ratios of 12.5 %, 25 %, 33 % and 50 %. The outputs of 27 binary-to-duty converter 16 and up-counter 13 are applied to a digital 28 comparator 17 in which they are compared with each other to produce a 29 high-level output when the digital value of counter 13 is greater than the , ,~ - ' ' - . , output of bina~-to-duty converter 16. It is seen therefore that the output 2 of comparator 17 is a sequence of constant-frequency pulses of a variable 3 duty ratio which increases stepwisely at 6-second intervals as shown in 4 Fig. 3. From the tone quality standpoint, the maximum duty ratio is set 50 s % as described above.
6 The output of cornparator 17 is applied to an AND gate 18 to which a 7 POCSAG tone pattem, say A-code pattern, is also applied. In this way, 8 the variable duty 2.6 kHz pulse sequence is modulated by the POCSAG
9 A-code pattern as shown in Fig. 4 and applied through an amplifier 19 to 10 the speaker 7. Loudspeaker 7 has a narrow band of frequency response 11 characteristic. This characteristic is sufficient to suppress the harmonic 12 components of the modulated alert tone pulse which may otherwise 3 cause changes in tone quality with variations of the duty ratio.
14 Therefore, the POCSAG tone pattern can be used for generating an S alert tone with successively escalating sound levels.
16 A modified form of the sound alarm circuit 6 is shown in Fig. 5. In this 7 modificationt a programmable counter 20 is used instead of the up-8 counter 13 and comparator 17. Programmable counter 20 is clocked by 19 the output of AND gate 10 and reset by the output of frequency divider 11. The output of binary-to-duty converter 16 is applied to 21 programmable counter 20 as a preset count value which decrements at 6 22 second intervals in response to the output of frequency divider 12 (Fig. 6),23 and hence the duty ratio of the tone pulses generated by programmable 24 counter 20 increases with the decrease in the preset count value.
2S Alternatively, the present invention can be further modified as shown 26 in Fig. 7 in which the down-counter is replaced with an up-counter 31 and 27 binary-to-duty converter 32 transforms the stepwisely incremental value 28 of the output of counter 31 to a stepwisely incremental duty ratio. A flip-29 flop 30 is provided having a set input terminal connected to the output of . .
.
. ~ - . - . -.,. ' : , , ' ' ', ' ': ' ' ' -, . . , ~ . . - , .,. ~
.
frequency divider 11 and a reset input terminal connected to the output of 2 programmable counter 34 whose program input is connected to the 3 output of binary-to-duty converter 32. An AND gate 33 is responsive to 4 the output of flip-flop 30 to pass the output of AND gate 10 to the clock s input of programmable counter 34. The output of flip-flop 30 is further 6 applied to the reset input of programmable counter 34 and one input of 7 AND gate 18.
8 As shown in Fig. 8, flip-flop 30 is triggered into a high-level, set 9 condition in response to each output pulse from frequency divider 11 to allow clock pulses from AND gate 10 to pass through AND gate 33 to the 11 programmable counter 34. The latter produces a high-level output when 12 the duty representing count value is reached and resets the flip-flop 30 to 13 a low-level condition, producing a tone pulse having a stepwisely 14 incremental duty ratio.
15 The foregoing description shows only one preferred embodiment of 16 the present invention. Various modifications are apparent to those skilled 17 in the art without departing from the scope of the present invention which 18 is only limited by the appended claims. Therefore, the embodiment 19 shown and described is only illustrative, not restrictive.
' ' , , , ' ' - . ~ .
s Fig. 2 is a block diagram of a sound alarm circuit of this invention;
6 Fig. 3 is a waveform diagram associated with the sound alarm circuit 7 of Fig. 2;
8 Fig. 4 is a waveform diagram of the tone pulses modulated with a 9 POCSAG A-code tone pattern;
Fig. 5 is a block diagram of a modified form of the sound alarm 1 1 circuit;
12 Fig. 6 is a waveform diagram associated with the sound alarm circuit 13 of Fig. 5;
14 Fig. 7 is a block diagram of an alternative form of the sound alarm circuit; and 16 Fig. 8 is a waveform diagram associated with the sound alarm circuit 17 of Fig. 7.
19 A radio pager of the present invention as represented in Fig. 1 20 comprises a front end 2 for converting paging signals received by antenna 21 1 to baseband signals for coupling to a waveshaper 3. The output of 22 waveshaper 3 is applied to a decoder 4 in which the received signal is 23 checked for a coincidence between a pager identifier contained in it and 24 the one stored in a PROM (programmable read only memory) 5. On 2 5 detecting a coincidence, decoder 4 alerts a sound alarm circuit 6 with a 26 POCSAG (Post Office Code Standardization Advisory Group) alert tone 27 signal having one of predetermined tone patterns or cadences. For 28 example, one such cadence is a cyclic sequence of 7/8-second ~N and 29 1/8-second OFF. Sound alarm circuit 6 modulates the tone signal with a (l , ~:
. . . . . ..
... . . ~ ; .
- . . .
- : . .. : ,. .-. . - --, , ' , . ....
variable duty pulse sequence and activates a loudspeaker 7. A reset 2 switch 8 is connected to the decoder 4 to be operated when the user 3 answers an incoming page.
4 As shown in Fig. 2, sound aiarm clrcuit 6 comprises an AND gate 10 s that is responsive to an enable signal from decoder 4 to pass high-6 frequency clock pulses from a clock source 9 to frequency dividers 11 and 7 12, and further to an up-counter 13 during the time the pager is being 8 alerted. As shown in Fig. 3, frequency divider 11 divides the frequency of 9 the clock to produce an output whose frequency determines the pitch of the alert tone, typically at 2.6 kHz, and frequency divider 12 divides that 11 clock frequency so that its output determines the rate at which the duty 12 ratio of the 2.6-kHz pulse sequence is varied. Typicatly, the duty ratio is 13 stepwisely varied at 6-second intervals. The output of frequency divider 14 11 is applied to the up-counter 13 as a reset pulse so that its output 15 represents a digital count value which continuously increments in response 16 to the clock pulse until it rapidly drops to zero in response to the reset 17 pulse. On the other hand, the output of frequency divider 12 is applied to 18 a down-counter 15 to produce a decremental binary count value which 19 represents the varying rate of the duty ratio. A monostable multivibrator 2 0 14 iS provided for producing a pulse for clearing the contents of down-21 counter 15 as soon as the pager is alerted.
22 The digital output of down~counter 15 is applied to a binary-to-duty 2 3 converter 16 which converts it to a digital value representing the duty ratio 24 of the 2.6-kHz pulse sequence for each 6-second interval. In a typical 25 example, binary-to-duty converter 16 successively generates outputs 2 6 representing duty ratios of 12.5 %, 25 %, 33 % and 50 %. The outputs of 27 binary-to-duty converter 16 and up-counter 13 are applied to a digital 28 comparator 17 in which they are compared with each other to produce a 29 high-level output when the digital value of counter 13 is greater than the , ,~ - ' ' - . , output of bina~-to-duty converter 16. It is seen therefore that the output 2 of comparator 17 is a sequence of constant-frequency pulses of a variable 3 duty ratio which increases stepwisely at 6-second intervals as shown in 4 Fig. 3. From the tone quality standpoint, the maximum duty ratio is set 50 s % as described above.
6 The output of cornparator 17 is applied to an AND gate 18 to which a 7 POCSAG tone pattem, say A-code pattern, is also applied. In this way, 8 the variable duty 2.6 kHz pulse sequence is modulated by the POCSAG
9 A-code pattern as shown in Fig. 4 and applied through an amplifier 19 to 10 the speaker 7. Loudspeaker 7 has a narrow band of frequency response 11 characteristic. This characteristic is sufficient to suppress the harmonic 12 components of the modulated alert tone pulse which may otherwise 3 cause changes in tone quality with variations of the duty ratio.
14 Therefore, the POCSAG tone pattern can be used for generating an S alert tone with successively escalating sound levels.
16 A modified form of the sound alarm circuit 6 is shown in Fig. 5. In this 7 modificationt a programmable counter 20 is used instead of the up-8 counter 13 and comparator 17. Programmable counter 20 is clocked by 19 the output of AND gate 10 and reset by the output of frequency divider 11. The output of binary-to-duty converter 16 is applied to 21 programmable counter 20 as a preset count value which decrements at 6 22 second intervals in response to the output of frequency divider 12 (Fig. 6),23 and hence the duty ratio of the tone pulses generated by programmable 24 counter 20 increases with the decrease in the preset count value.
2S Alternatively, the present invention can be further modified as shown 26 in Fig. 7 in which the down-counter is replaced with an up-counter 31 and 27 binary-to-duty converter 32 transforms the stepwisely incremental value 28 of the output of counter 31 to a stepwisely incremental duty ratio. A flip-29 flop 30 is provided having a set input terminal connected to the output of . .
.
. ~ - . - . -.,. ' : , , ' ' ', ' ': ' ' ' -, . . , ~ . . - , .,. ~
.
frequency divider 11 and a reset input terminal connected to the output of 2 programmable counter 34 whose program input is connected to the 3 output of binary-to-duty converter 32. An AND gate 33 is responsive to 4 the output of flip-flop 30 to pass the output of AND gate 10 to the clock s input of programmable counter 34. The output of flip-flop 30 is further 6 applied to the reset input of programmable counter 34 and one input of 7 AND gate 18.
8 As shown in Fig. 8, flip-flop 30 is triggered into a high-level, set 9 condition in response to each output pulse from frequency divider 11 to allow clock pulses from AND gate 10 to pass through AND gate 33 to the 11 programmable counter 34. The latter produces a high-level output when 12 the duty representing count value is reached and resets the flip-flop 30 to 13 a low-level condition, producing a tone pulse having a stepwisely 14 incremental duty ratio.
15 The foregoing description shows only one preferred embodiment of 16 the present invention. Various modifications are apparent to those skilled 17 in the art without departing from the scope of the present invention which 18 is only limited by the appended claims. Therefore, the embodiment 19 shown and described is only illustrative, not restrictive.
' ' , , , ' ' - . ~ .
Claims (5)
1. A radio pager comprising:
receive means for receiving a paging signal containing a unique identifier identifying said radio pager and an alert tone pattern;
pulse generating means for generating constant audio frequency pulses having a duty ratio increasing as a function of time in response to receipt of said paging signal;
modulating means for modulating said pulses with said alert tone pattern; and sound generating means activated by said modulated pulses.
receive means for receiving a paging signal containing a unique identifier identifying said radio pager and an alert tone pattern;
pulse generating means for generating constant audio frequency pulses having a duty ratio increasing as a function of time in response to receipt of said paging signal;
modulating means for modulating said pulses with said alert tone pattern; and sound generating means activated by said modulated pulses.
2. A radio pager as claimed in claim 1, wherein said alert tone pattern is a POCSAG (Post Office Code Standardization Advisory Group) tone pattern.
3. A radio pager as claimed in claim 1, wherein said pulse generating means comprises:
a clock source for generating pulses at a clock frequency;
a first frequency divider for dividing the clock frequency of said pulses to produce pulses at an audio frequency;
a second frequency divider for dividing the clock frequency of said pulses to produce pulses at a frequency much lower than said audio-frequency;
means responsive to each of the audio frequency pulses for generating a series of first digital values which increase synchronously with said clock frequency pulses;
means for generating second digital values which successively decrease in response to said lower frequency pulses;
means for comparing said first and second digital values to produce an output signal when said first digital values are greater than said second digital values, said modulating means being coupled to said comparing means.
a clock source for generating pulses at a clock frequency;
a first frequency divider for dividing the clock frequency of said pulses to produce pulses at an audio frequency;
a second frequency divider for dividing the clock frequency of said pulses to produce pulses at a frequency much lower than said audio-frequency;
means responsive to each of the audio frequency pulses for generating a series of first digital values which increase synchronously with said clock frequency pulses;
means for generating second digital values which successively decrease in response to said lower frequency pulses;
means for comparing said first and second digital values to produce an output signal when said first digital values are greater than said second digital values, said modulating means being coupled to said comparing means.
4. A radio pager as claimed in claim 1, wherein said pulse generating means comprises:
a clock source for generating pulses at a clock frequency;
a first frequency divider for dividing the clock frequency of said pulses to produce pulses at an audio frequency;
a second frequency divider for dividing the clock frequency of said pulses to produce pulses at a frequency much lower than said audio-frequency;
means for generating digital values which successively decrease in response to said lower frequency pulses; and presettable counter means having a count value successively preset to said digital values, said presettable counter means being responsive to each of the audio frequency pulses for counting said clock frequency pulses to produce an output pulse having a leading edge coinciding with time at which the count of the clock frequency pulses reaches the preset value and a trailing edge coinciding with each of said audio frequency pulses, said modulating means being coupled to said presettable counter means.
a clock source for generating pulses at a clock frequency;
a first frequency divider for dividing the clock frequency of said pulses to produce pulses at an audio frequency;
a second frequency divider for dividing the clock frequency of said pulses to produce pulses at a frequency much lower than said audio-frequency;
means for generating digital values which successively decrease in response to said lower frequency pulses; and presettable counter means having a count value successively preset to said digital values, said presettable counter means being responsive to each of the audio frequency pulses for counting said clock frequency pulses to produce an output pulse having a leading edge coinciding with time at which the count of the clock frequency pulses reaches the preset value and a trailing edge coinciding with each of said audio frequency pulses, said modulating means being coupled to said presettable counter means.
5. A radio pager as claimed in claim 1, wherein said pulse generating means comprises:
a clock source for generating pulses at a clock frequency;
a first frequency divider for dividing the clock frequency of said pulses to produce pulses at an audio frequency;
a second frequency divider for dividing the clock frequency of said pulses to produce pulses at a frequency much lower than said audio-frequency;
means for generating digital values which successively increase in response to said lower frequency pulses; and bistable means arranged to be triggered into a first output state in response to each of the audio frequency pulses and triggered into a second output state in response to a reset signal applied thereto, said modulating means being coupled to said bistable means; and presettable counter means having a count value successively preset to said digital values, said presettable counter means being responsive to the first output state of said bistable means for counting said clock frequency pulses to produce an output pulse to said bistable means as said reset signal the count of the clock frequency pulses reaches the preset value.
a clock source for generating pulses at a clock frequency;
a first frequency divider for dividing the clock frequency of said pulses to produce pulses at an audio frequency;
a second frequency divider for dividing the clock frequency of said pulses to produce pulses at a frequency much lower than said audio-frequency;
means for generating digital values which successively increase in response to said lower frequency pulses; and bistable means arranged to be triggered into a first output state in response to each of the audio frequency pulses and triggered into a second output state in response to a reset signal applied thereto, said modulating means being coupled to said bistable means; and presettable counter means having a count value successively preset to said digital values, said presettable counter means being responsive to the first output state of said bistable means for counting said clock frequency pulses to produce an output pulse to said bistable means as said reset signal the count of the clock frequency pulses reaches the preset value.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2418502A JPH04227134A (en) | 1990-12-29 | 1990-12-29 | Selective radio call receiver |
| JP2-418502 | 1990-12-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2058536A1 true CA2058536A1 (en) | 1992-06-30 |
Family
ID=18526335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002058536A Abandoned CA2058536A1 (en) | 1990-12-29 | 1991-12-27 | Radio pager tone alarm circuit for generating variable duty constant audio frequency pulses modulated with unique tone pattern |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0493973B1 (en) |
| JP (1) | JPH04227134A (en) |
| AU (1) | AU649505B2 (en) |
| CA (1) | CA2058536A1 (en) |
| DE (1) | DE69124974T2 (en) |
| HK (1) | HK1002413A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09186744A (en) * | 1995-12-29 | 1997-07-15 | Nec Corp | Radio communication equipment |
| KR0173402B1 (en) * | 1996-05-18 | 1999-04-01 | 김광호 | Ring volume control method of telephone |
| US6433673B1 (en) | 1998-09-25 | 2002-08-13 | Conexant Systems, Inc. | Digital enunciator, process and communication system employing same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2287732A1 (en) * | 1974-10-09 | 1976-05-07 | Daumas Sa Ets | Selective sound alarm system - two low frequency sources to produce sound using binary memory |
| US4237448A (en) * | 1979-04-30 | 1980-12-02 | Motorola, Inc. | Pager with escalating audio alert signal level |
| JPH0754990B2 (en) * | 1986-09-16 | 1995-06-07 | 日本電気株式会社 | Multi-report device for wireless selective call receiver |
| AU6718190A (en) * | 1989-11-06 | 1991-05-31 | Motorola, Inc. | Selective call receiver |
-
1990
- 1990-12-29 JP JP2418502A patent/JPH04227134A/en active Pending
-
1991
- 1991-12-27 EP EP91312066A patent/EP0493973B1/en not_active Expired - Lifetime
- 1991-12-27 CA CA002058536A patent/CA2058536A1/en not_active Abandoned
- 1991-12-27 DE DE69124974T patent/DE69124974T2/en not_active Expired - Fee Related
- 1991-12-30 AU AU90102/91A patent/AU649505B2/en not_active Ceased
-
1998
- 1998-02-23 HK HK98101363A patent/HK1002413A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| HK1002413A1 (en) | 1998-08-21 |
| JPH04227134A (en) | 1992-08-17 |
| AU649505B2 (en) | 1994-05-26 |
| EP0493973B1 (en) | 1997-03-05 |
| EP0493973A1 (en) | 1992-07-08 |
| AU9010291A (en) | 1992-07-02 |
| DE69124974D1 (en) | 1997-04-10 |
| DE69124974T2 (en) | 1997-06-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |