CA2220829C - Method of operating a modem in the presence of interrupted dial tone - Google Patents
Method of operating a modem in the presence of interrupted dial tone Download PDFInfo
- Publication number
- CA2220829C CA2220829C CA 2220829 CA2220829A CA2220829C CA 2220829 C CA2220829 C CA 2220829C CA 2220829 CA2220829 CA 2220829 CA 2220829 A CA2220829 A CA 2220829A CA 2220829 C CA2220829 C CA 2220829C
- Authority
- CA
- Canada
- Prior art keywords
- modem
- dial tone
- dial
- interrupted
- stuttered
- 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 - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/42—Systems providing special services or facilities to subscribers
- H04M3/50—Centralised arrangements for answering calls; Centralised arrangements for recording messages for absent or busy subscribers ; Centralised arrangements for recording messages
- H04M3/53—Centralised arrangements for recording incoming messages, i.e. mailbox systems
- H04M3/537—Arrangements for indicating the presence of a recorded message, whereby the presence information might include a preview or summary of the message
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Telephonic Communication Services (AREA)
Abstract
According to the present invention, a method is provided enabling an analog mode m to dial out while a dial tone is interrupted or stuttered due to at least one un heard message at a Central Office for a subscriber to Call Answer is provided . Call A nswer is an automated voice messaging system which causes the dial tone of a phone lin e connected to the modem, to be either interrupted or stuttered when a message is waiting for the subscriber. Users of the present invention are able to receive o n-line access faster than users of the prior art. The method of the present invention implements a software program within the modem. By comparing the elapsed length of the dial tone with two predetermined time values (a maximum and a minimum), t he method detects the presence and status of the dial tone and informs the modem of the status of the dial tone. Provided that a dial tone is present, whether uninterru pted interrupted or stuttered, the modem proceeds to dial out.
Description
METHOD OF OPERATING A MODEM IN
THE PRESENCE OF INTERRUPTED DIAL TONE
FIELD OF THE INVENTION
s This invention relates in general to analog modems and more specifically to an analog modem which is capable of dialing out when a dial tone is interrupted, stuttered or lmint~,rrupted.
Prior art modems suffer from the disadvantage of requiring steady u~ tell ~ted dial tone in order to dial out. The presence of at least one unheard message in a voice mailbox for a subscriber's line, in connection with which a central office Call ~nswer 5 feature has been activated, causes an interrupted or stuttered dial tone on the line. In order for the modem to dial out, the interrupted or stuttered dial tone must be returned to its regular u~inl~llupled state, which requires the subscriber of the phone line to retrieve unheard messages from the voice mailbox. The inability of prior art modems to dial out in the presence of interrupted dial tone imposes delays in modem activation 20 and frustration for the modem user who wishes to have quick access to on-line features via the modem.
SIJMMARY OF THE rNVENTION
25 The present invention is directed at a solution to the problem of allowing modems to dial out when the dial tone is interrupted or stuttered.
~ccording to the present invention, a method is provided which allows a modem todial out provided that a dial tone is present on the phone line connected to the modem.
30 Users of the present invention are able to rece*e on-line access faster than users of the prior art. The method implements a software program within the modem. By comparing the elapsed length of the dial tone with two preclet~rrnined time values (a CA 02220829 1997-ll-12 m~xi""l,., and a ~ -il lllllll), the method detects the presence and status of the dial tone and informs the modem of the status of the dial tone. Provided that a dial tone is present, whether nnint~rrupted, interrupted or stuttered, the modem proceeds to dial out.
According to one aspect of the present invention, there is provided a method foroperating a modem, connected to a phone line, in the presence of interrupted dial tone on the phone line comprising the steps of:
~0 a) requesting and receiving elapsed time since the dial tone was on;
b) comparing the elapsed time to a first predetermined time value and ceasing use of the modem if the elapsed time is greater than the first predetermined time value;
C) if the elapsed time is less than the first predetermined time value, then comparing the elapsed time to a second predetermined time value which is less than the first pre-let~rmined time value and ceasing use of the modem if the elapsed time is less than the second preclet.ormined time value; and d) if the elapsed time is greater than the second predetermined time value,~0 c~n~ing the modem to dial out on the phone line.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is described herein below with reference to th25 accompanying drawings, in which:
Figure 1 is a block diagram of a well-known modem setup; and Figure 2 is a flowchart showing the process by which a modem deduces the presence~0 and status of a dial tone in accordance with the pleft;ll~d embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to Figure 1, a computer 1 and a telephone 3 are shown connected to an ~xtPrn~l modem 5. Although an ext~rn~l modem is shown, the modem may 5 ~lt~-rn~tively be an intern~l modem within the computer 1. The modem 5 is further connected to a phone jack 7. The phone jack 7 is connected to a phone line 9 which m~int~in~ a connection with a central of fice 8 where all telephone features areorigin~te~l 10 To initiate a connection with the telephone central office 8 via phone line 9, TELIN
and TELOUT termin~l.s of the modem 5 are connected to the telephone Tip and Ringtermin~ls (normally located at Pin 3 and Pin 4 of the telephone jack 7). When the modem 5 goes off hook, the modem detects if the dial tone is ON by executing theprogram CHK_TONE which simply reads the Input/Output address $0B on the 15 modem chip. If bit 7 of this address is high, the tone is acknowledged to be On, otherwise, the tone is acknowledged to be Off. Upon receiving the dial tone, themodem 5 goes offhook and the modem 5 passes through a series of call progress states beginning with Wait_DialO and proceeding to Parse_DigitsO and then finally to ConnectO. When in the connected state, Dual Tone Multi Frequency (DTMF) signals 20 are sent to the central of fice 8 in the usual manner. All these programs will be well known to those skilled in the art.
However, in accordance with the principles of the present invention, a method isprovided for enabling the modem 5 to dial out while a dial tone is interrupted or 2s stuttered.
The status of the dial tone is det~ rmined by a computer program located within the modem whose syntax is shown herein below:
?DIALSTABLE: DB 08 ; Mitel changed April 15, 1997 for US
to work ; 80 ms CHK_DIALTONE: ; Examine ON duration LDRP R4, MSlOCLOCK
; Get time elapsed since tone wa~ on CMRPIM R4, DEBOUNCE_TIME
; More than the debounce time?
BCC ?DIALT_CHK
SETFLD DEBOUNCE_DONE
: ; Indicate there is no dialtone SETFLD VALID_CADENCE
RTS
?DIAL_CHK:
CMR R4, DIALSTABLE
; For primary dial tone BCC ByeCHK_RESULTS
SETFLD FO~ND_DIALONE
; Indicate dial tone detected RTS
ByeCHK_RESULTS:
RTS
The computer program listed herein above, may be represented by the algolill, 1ll shown in the flowchart of Figure 2. After the constant ?DIALSTABLE has been set, at step 10 the CHK_DL~LTONE program is called for ~X~minin~ the ON
duration of the dial tone previously detected using CHK_TONE discussed above. The modem 5 then requests the elapsed time since the dial tone has been on, shown in step 12.
The elapsed time is stored in the MS 1 OCLOCK variable and loaded into a register, R4, using the command line LDRP R4, MSl0CLOCK. MS10CLOCK is a software timer which is simply a byte in memory working like a counter. The value of MS l OCLOCK increases every 10 ms in an interrupt service routine of the above program. The following section of code shows how the MS 1 OCLOCK program runs:
INC MSlOCLOCK ; Increment 10 ms clock low byte BNE ?Exit_IRQ ; breal~ if not wrap time lNC MSlOCLOCK+l , Increment 10 ms clock mid byte BNE ?Exit_IRQ ; break if not wrap time rNC MS 1 OCLOCK+2 ; Increment 10 ms clock high byte From this program, it is clear that MSCLOCK+2 = $FF(256) MSlOCLOCK+l and MS10CLOCK+1 = $FF(256) MSlOCLOCK where the value $FF is a decimal value of 256.
To initialize these variables, the following section of code is used:
LDA #OOH
STA MSlOCLOCK
STA MS 1 OCLOCK+l STA MSlOCLOCK+2 After loading the elapsed time into register R4, the modem compares this value to a 20 predetermined value (step 14). The command CMRPIM R4, DEBOUNCE_TIME
compares the value in register R4 with the predetermined constant DEBO~CE_TIME.
If the elapsed time (retrieved in step 12 as MSlOCLOCK) is greater than the 2s pre~letermined constant (in the preferred embodiment chosen to be 2 s), the DEBOUNCE_DONE flag (step 16) sets and modem use ceases at step 18. The instruction SETFT n DEBOUNCE_DONE informs the modem that dialing out is not possible. The instruction RTS returns the computer program back to the main body of the computer 30 code, which does not form part of the present invention but would be well known by persons skilled in the art. Otherwise, if the elapsed time is less than the preclet~rrnined constant, the modem 5 checks with the constant DIALSTABLE discussed below (step 20). This branch operation is achieved through the instruction BCC ?DIALT_CHK
which causes the program to jump to the ?DIALT_CHK procedure if the value in R4 is less than the value in DEBO~NCE_TIME (step 14).
In step 20, the R4 value is compared to a second pre-letermined time value to ensure s that the dial tone is stable. This second compare produces a range for which the dial tone must fall within before the modem may dial out. The instruction CMR R4, DL~LSTABLE compares the elapsed time found in step 12 with the predetermined constant DIALSTABLE. If the value in register R4 is found to be less than the value of 80 ms (the value chosen in the pl~;rt;lled embodiment), the program jumps to the 10 ByeCHK_RESULTS procedure (step 22) and modem use ceases at step 24. This is achieved by the comm~n~l~ BCC ByeCHK_RESULTS and RTS respectively.
Otherwise, if the value in R4 is greater than DIALSTABLE, then dial tone is deemed to have been found (step 26) and the modem 5 dials out (step 28). This is achieved through the instruction SETFLD FOUND_DL~LTONE which informs the modem 15 that dialing out is possible.
Tn summary, the method of the present invention, allows a modem to properly detect dial tone, whether the tone is uninterrupted, stuttered or int~llu~t~d. According to the pler~lled embodiment, the modem is able to detect interrupted or stuttered dial tones 20 from 80 to 160 ms +/- 5 ms (i.e. silent intervals up to 160 ms +/- 5 ms are recognized as interrupted or stuttered dial tone). Although Call Answer is listed as reason for causing the interrupted or stuttered dial tone, it should be noted that this modem is able to detect the presence of the dial tone of the connected phone line and is not used solely to detect interrupted or stuttered dial tones caused by the Call Answer feature.
It will be appreciated that, although a particular embodiment has been described and illustrated in detail, various changes and modifications may be made. One such change is in the name of the variables within the computer program. Provided that all name changes are made globally (i.e. throughout the program), the program will 30 function in the same manner. Also, in the plt;r~llt;d embodiment, Call Answer is listed as the source of the interrupted or stuttered dial tone. It should be noted that there may be other reasons as to why a dial tone might become interrupted or stuttered yet remain stable. Another contemplated modification is in the choice of the pre~letermined time values. Although the values of 2 s and 80 ms have been chosen for DEBOUNCE_TIME and DIALSTABLE, respectively in the preferred embodiment of the present invention, they may be changed to accommodate various 5 other features telephone companies may offer. All such changes and modifications may be made without departing from the sphere and scope of the invention as defined by the claims appended hereto.
THE PRESENCE OF INTERRUPTED DIAL TONE
FIELD OF THE INVENTION
s This invention relates in general to analog modems and more specifically to an analog modem which is capable of dialing out when a dial tone is interrupted, stuttered or lmint~,rrupted.
Prior art modems suffer from the disadvantage of requiring steady u~ tell ~ted dial tone in order to dial out. The presence of at least one unheard message in a voice mailbox for a subscriber's line, in connection with which a central office Call ~nswer 5 feature has been activated, causes an interrupted or stuttered dial tone on the line. In order for the modem to dial out, the interrupted or stuttered dial tone must be returned to its regular u~inl~llupled state, which requires the subscriber of the phone line to retrieve unheard messages from the voice mailbox. The inability of prior art modems to dial out in the presence of interrupted dial tone imposes delays in modem activation 20 and frustration for the modem user who wishes to have quick access to on-line features via the modem.
SIJMMARY OF THE rNVENTION
25 The present invention is directed at a solution to the problem of allowing modems to dial out when the dial tone is interrupted or stuttered.
~ccording to the present invention, a method is provided which allows a modem todial out provided that a dial tone is present on the phone line connected to the modem.
30 Users of the present invention are able to rece*e on-line access faster than users of the prior art. The method implements a software program within the modem. By comparing the elapsed length of the dial tone with two preclet~rrnined time values (a CA 02220829 1997-ll-12 m~xi""l,., and a ~ -il lllllll), the method detects the presence and status of the dial tone and informs the modem of the status of the dial tone. Provided that a dial tone is present, whether nnint~rrupted, interrupted or stuttered, the modem proceeds to dial out.
According to one aspect of the present invention, there is provided a method foroperating a modem, connected to a phone line, in the presence of interrupted dial tone on the phone line comprising the steps of:
~0 a) requesting and receiving elapsed time since the dial tone was on;
b) comparing the elapsed time to a first predetermined time value and ceasing use of the modem if the elapsed time is greater than the first predetermined time value;
C) if the elapsed time is less than the first predetermined time value, then comparing the elapsed time to a second predetermined time value which is less than the first pre-let~rmined time value and ceasing use of the modem if the elapsed time is less than the second preclet.ormined time value; and d) if the elapsed time is greater than the second predetermined time value,~0 c~n~ing the modem to dial out on the phone line.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is described herein below with reference to th25 accompanying drawings, in which:
Figure 1 is a block diagram of a well-known modem setup; and Figure 2 is a flowchart showing the process by which a modem deduces the presence~0 and status of a dial tone in accordance with the pleft;ll~d embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to Figure 1, a computer 1 and a telephone 3 are shown connected to an ~xtPrn~l modem 5. Although an ext~rn~l modem is shown, the modem may 5 ~lt~-rn~tively be an intern~l modem within the computer 1. The modem 5 is further connected to a phone jack 7. The phone jack 7 is connected to a phone line 9 which m~int~in~ a connection with a central of fice 8 where all telephone features areorigin~te~l 10 To initiate a connection with the telephone central office 8 via phone line 9, TELIN
and TELOUT termin~l.s of the modem 5 are connected to the telephone Tip and Ringtermin~ls (normally located at Pin 3 and Pin 4 of the telephone jack 7). When the modem 5 goes off hook, the modem detects if the dial tone is ON by executing theprogram CHK_TONE which simply reads the Input/Output address $0B on the 15 modem chip. If bit 7 of this address is high, the tone is acknowledged to be On, otherwise, the tone is acknowledged to be Off. Upon receiving the dial tone, themodem 5 goes offhook and the modem 5 passes through a series of call progress states beginning with Wait_DialO and proceeding to Parse_DigitsO and then finally to ConnectO. When in the connected state, Dual Tone Multi Frequency (DTMF) signals 20 are sent to the central of fice 8 in the usual manner. All these programs will be well known to those skilled in the art.
However, in accordance with the principles of the present invention, a method isprovided for enabling the modem 5 to dial out while a dial tone is interrupted or 2s stuttered.
The status of the dial tone is det~ rmined by a computer program located within the modem whose syntax is shown herein below:
?DIALSTABLE: DB 08 ; Mitel changed April 15, 1997 for US
to work ; 80 ms CHK_DIALTONE: ; Examine ON duration LDRP R4, MSlOCLOCK
; Get time elapsed since tone wa~ on CMRPIM R4, DEBOUNCE_TIME
; More than the debounce time?
BCC ?DIALT_CHK
SETFLD DEBOUNCE_DONE
: ; Indicate there is no dialtone SETFLD VALID_CADENCE
RTS
?DIAL_CHK:
CMR R4, DIALSTABLE
; For primary dial tone BCC ByeCHK_RESULTS
SETFLD FO~ND_DIALONE
; Indicate dial tone detected RTS
ByeCHK_RESULTS:
RTS
The computer program listed herein above, may be represented by the algolill, 1ll shown in the flowchart of Figure 2. After the constant ?DIALSTABLE has been set, at step 10 the CHK_DL~LTONE program is called for ~X~minin~ the ON
duration of the dial tone previously detected using CHK_TONE discussed above. The modem 5 then requests the elapsed time since the dial tone has been on, shown in step 12.
The elapsed time is stored in the MS 1 OCLOCK variable and loaded into a register, R4, using the command line LDRP R4, MSl0CLOCK. MS10CLOCK is a software timer which is simply a byte in memory working like a counter. The value of MS l OCLOCK increases every 10 ms in an interrupt service routine of the above program. The following section of code shows how the MS 1 OCLOCK program runs:
INC MSlOCLOCK ; Increment 10 ms clock low byte BNE ?Exit_IRQ ; breal~ if not wrap time lNC MSlOCLOCK+l , Increment 10 ms clock mid byte BNE ?Exit_IRQ ; break if not wrap time rNC MS 1 OCLOCK+2 ; Increment 10 ms clock high byte From this program, it is clear that MSCLOCK+2 = $FF(256) MSlOCLOCK+l and MS10CLOCK+1 = $FF(256) MSlOCLOCK where the value $FF is a decimal value of 256.
To initialize these variables, the following section of code is used:
LDA #OOH
STA MSlOCLOCK
STA MS 1 OCLOCK+l STA MSlOCLOCK+2 After loading the elapsed time into register R4, the modem compares this value to a 20 predetermined value (step 14). The command CMRPIM R4, DEBOUNCE_TIME
compares the value in register R4 with the predetermined constant DEBO~CE_TIME.
If the elapsed time (retrieved in step 12 as MSlOCLOCK) is greater than the 2s pre~letermined constant (in the preferred embodiment chosen to be 2 s), the DEBOUNCE_DONE flag (step 16) sets and modem use ceases at step 18. The instruction SETFT n DEBOUNCE_DONE informs the modem that dialing out is not possible. The instruction RTS returns the computer program back to the main body of the computer 30 code, which does not form part of the present invention but would be well known by persons skilled in the art. Otherwise, if the elapsed time is less than the preclet~rrnined constant, the modem 5 checks with the constant DIALSTABLE discussed below (step 20). This branch operation is achieved through the instruction BCC ?DIALT_CHK
which causes the program to jump to the ?DIALT_CHK procedure if the value in R4 is less than the value in DEBO~NCE_TIME (step 14).
In step 20, the R4 value is compared to a second pre-letermined time value to ensure s that the dial tone is stable. This second compare produces a range for which the dial tone must fall within before the modem may dial out. The instruction CMR R4, DL~LSTABLE compares the elapsed time found in step 12 with the predetermined constant DIALSTABLE. If the value in register R4 is found to be less than the value of 80 ms (the value chosen in the pl~;rt;lled embodiment), the program jumps to the 10 ByeCHK_RESULTS procedure (step 22) and modem use ceases at step 24. This is achieved by the comm~n~l~ BCC ByeCHK_RESULTS and RTS respectively.
Otherwise, if the value in R4 is greater than DIALSTABLE, then dial tone is deemed to have been found (step 26) and the modem 5 dials out (step 28). This is achieved through the instruction SETFLD FOUND_DL~LTONE which informs the modem 15 that dialing out is possible.
Tn summary, the method of the present invention, allows a modem to properly detect dial tone, whether the tone is uninterrupted, stuttered or int~llu~t~d. According to the pler~lled embodiment, the modem is able to detect interrupted or stuttered dial tones 20 from 80 to 160 ms +/- 5 ms (i.e. silent intervals up to 160 ms +/- 5 ms are recognized as interrupted or stuttered dial tone). Although Call Answer is listed as reason for causing the interrupted or stuttered dial tone, it should be noted that this modem is able to detect the presence of the dial tone of the connected phone line and is not used solely to detect interrupted or stuttered dial tones caused by the Call Answer feature.
It will be appreciated that, although a particular embodiment has been described and illustrated in detail, various changes and modifications may be made. One such change is in the name of the variables within the computer program. Provided that all name changes are made globally (i.e. throughout the program), the program will 30 function in the same manner. Also, in the plt;r~llt;d embodiment, Call Answer is listed as the source of the interrupted or stuttered dial tone. It should be noted that there may be other reasons as to why a dial tone might become interrupted or stuttered yet remain stable. Another contemplated modification is in the choice of the pre~letermined time values. Although the values of 2 s and 80 ms have been chosen for DEBOUNCE_TIME and DIALSTABLE, respectively in the preferred embodiment of the present invention, they may be changed to accommodate various 5 other features telephone companies may offer. All such changes and modifications may be made without departing from the sphere and scope of the invention as defined by the claims appended hereto.
Claims (4)
1. A method for operating a modem, connected to a phone line, in the presence ofinterrupted dial tone on said phone line comprising the steps of:
a) requesting and receiving elapsed time since said dial tone was on;
b) comparing said elapsed time to a first predetermined time value and ceasing use of said modem if said elapsed time is greater than said first predetermined time value;
c) if said elapsed time is less than said first predetermined time value, then comparing said elapsed time to a second predetermined time value which is less than said first predetermined time value and ceasing use of said modem if said elapsed time is less than said second predetermined time value; and d) if said elapsed time is greater than said second predetermined time value, causing said modem to dial out on said phone line.
a) requesting and receiving elapsed time since said dial tone was on;
b) comparing said elapsed time to a first predetermined time value and ceasing use of said modem if said elapsed time is greater than said first predetermined time value;
c) if said elapsed time is less than said first predetermined time value, then comparing said elapsed time to a second predetermined time value which is less than said first predetermined time value and ceasing use of said modem if said elapsed time is less than said second predetermined time value; and d) if said elapsed time is greater than said second predetermined time value, causing said modem to dial out on said phone line.
2. The method of claim 1 wherein said first predetermined value is 2 seconds.
3. The method of claim 1 wherein said second predetermined value is between 80 and 160 ms.
4. The method of claim 1 wherein said modem is an analog modem.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2220829 CA2220829C (en) | 1997-11-12 | 1997-11-12 | Method of operating a modem in the presence of interrupted dial tone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2220829 CA2220829C (en) | 1997-11-12 | 1997-11-12 | Method of operating a modem in the presence of interrupted dial tone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2220829C true CA2220829C (en) | 2001-01-02 |
Family
ID=4161755
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2220829 Expired - Fee Related CA2220829C (en) | 1997-11-12 | 1997-11-12 | Method of operating a modem in the presence of interrupted dial tone |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2220829C (en) |
-
1997
- 1997-11-12 CA CA 2220829 patent/CA2220829C/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5963629A (en) | Method for embodying automatic call in a keyphone system | |
| US5859896A (en) | Telephone line automatic prefix dialer | |
| JP3718249B2 (en) | Communication device | |
| JPH0646124A (en) | Telephone set with automatic responding function | |
| US5442764A (en) | Digital signal processing having improved execution efficiency | |
| US4513175A (en) | Automatic calling systems for accessing communications networks | |
| JP3157004B2 (en) | Circuit and method for automatic memory dial operation | |
| CA2220829C (en) | Method of operating a modem in the presence of interrupted dial tone | |
| US5974084A (en) | Method of operating a modem in the presence of interrupted dial tone | |
| US20020067804A1 (en) | Method and apparatus for recording and replaying messages | |
| JP2000165500A (en) | Call sound type based on call relating information | |
| AU723629B2 (en) | Apparatus and method for providing music-on-hold service in key telephone system | |
| KR100480241B1 (en) | How to set up call rejection in keyphone system | |
| SE9601951D0 (en) | Procedure for automatically connecting incoming signal to outgoing location in automatic answering machine where tripartite call service is subscribed | |
| KR100474681B1 (en) | How to provide music | |
| KR20000041842A (en) | Method for abbreviating dial including dial after call start in exchange system | |
| JPS61176275A (en) | Facsimile equipment | |
| KR19980082968A (en) | How to automatically call continuously | |
| JP2669915B2 (en) | Call weighting method | |
| NZ260037A (en) | Telephone subset: automatic dual-tone multifrequency or decadic dialling in accordance with tone signal from exchange | |
| KR100206306B1 (en) | Voice message transmission method in keyphone system | |
| JPS5936470A (en) | On-line interrupting system | |
| KR100226768B1 (en) | Telephone with automatic redialing function | |
| KR950030568A (en) | Information phone number display and automatic call diagram circuit and its operation method | |
| KR920017415A (en) | How to Forward an Incoming Message from an Answering Phone |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |