WO1999033280A1 - Releve d'impulsions decimales dans une porteuse a boucle numerique - Google Patents
Releve d'impulsions decimales dans une porteuse a boucle numerique Download PDFInfo
- Publication number
- WO1999033280A1 WO1999033280A1 PCT/US1998/026873 US9826873W WO9933280A1 WO 1999033280 A1 WO1999033280 A1 WO 1999033280A1 US 9826873 W US9826873 W US 9826873W WO 9933280 A1 WO9933280 A1 WO 9933280A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- hook
- channel unit
- signals
- message
- cards
- Prior art date
Links
- 238000000034 method Methods 0.000 claims abstract description 22
- 230000008569 process Effects 0.000 claims abstract description 6
- 230000005540 biological transmission Effects 0.000 description 10
- 230000011664 signaling Effects 0.000 description 7
- 230000007704 transition Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 239000000370 acceptor Substances 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
- H04Q1/18—Electrical details
- H04Q1/30—Signalling arrangements; Manipulation of signalling currents
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
- H04Q1/18—Electrical details
- H04Q1/30—Signalling arrangements; Manipulation of signalling currents
- H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
Definitions
- Telecommunications access terminals connect subscriber lines, such as POTS (Plain Old Telephone Service) lines, to telecommunications exchanges and other telecommunications equipment .
- An access terminal contains channel unit card slots that accept channel unit cards.
- the channel unit cards, or line cards convert analog or digital signals from subscriber lines into formatted digital data signals. Different types of channel unit cards service different types of subscriber lines .
- dial pulsing also known as rotary dialing
- regular momentary interruptions of a direct or alternating current at the subscriber end indicate the value of the dialed number or character. For example, three interruptions can represent the digit 3.
- DT F Dual Tone Multi-Frequency
- PBX Private Branch Exchange
- a method of handling subscriber line signals includes sensing, in a channel unit card, one or more on-hook/off-hook signals, where the on-hook/off-hook signals correspond to a dialed alphanumeric character.
- a message-oriented signal which includes the value of the dialed alphanumeric character, is formed in the channel unit card. The message-oriented signal is delivered to an access terminal connected to the channel unit card.
- a method of handling subscriber line signals in a telecommunications system includes sensing on-hook/off-hook signals in the channel unit cards and processing the on-hook/off- hook signals in the channel unit cards in a distributed manner.
- Message-oriented signals are delivered from the channel unit cards to the access terminal .
- Each of the message-oriented signals includes a value representing a dialed digit corresponding to the on-hook/off-hook signals received in a respective one of the channel unit cards.
- a channel unit card in another aspect, includes a hook detector circuit for sensing on-hook/off-hook signals on subscriber lines and for setting the state of a bit based on the received on-hook/off-hook signals.
- the channel unit card further includes a processor configured to scan the bit and to form a message-oriented signal based on the bit scanning.
- the message-oriented signal includes a value corresponding to the on-hook/off- hook signals.
- a telecommunications system can include an access terminal and multiple channel unit cards as described above. The channel unit cards are coupled to the access terminal .
- the channel unit cards are configured to sense on-hook/off-hook signals on subscriber lines coupled to respective ones of the channel unit cards .
- Each channel unit card is configured to process received on-hook/off-hook signals and to send a message-oriented signal to the access terminal.
- Each message-oriented signal includes a value representing a dialed digit corresponding to on-hook/off- hook signals received in the respective one of the channel unit cards.
- the channel unit card can determine whether a digit has been dialed at a subscriber device, such as a telephone, based on the bit scanning.
- the channel unit card also can determine the value of the digit or other alphanumeric character based on the bit scanning.
- the processor in the channel unit card can be configured to determine whether a digit has been dialed at a subscriber device based on the bit scanning.
- the processor also can be configured to determine the value represented by the on-hook/off-hook signals .
- the channel unit card can include a counter, and the processor can be configured to increment a value stored in the counter based on the state of the bit set by the hook detector circuit.
- the processor also can be configured to form the message-oriented signal based on a value stored in the counter.
- the access terminal and channel unit cards form part of a digital loop carrier system.
- the channel unit cards can be, for example, POTS or other line cards.
- Various implementations may provide one or more of the following advantages.
- the terminal By distributing the performance of dial pulse collection among multiple channel unit cards coupled to an access terminal, the terminal can devote more time to other call control and processing functions.
- using message- oriented signaling for messages transmitted between the channel unit cards at the access terminal and a central processor in the access terminal can free up additional bandwidth to be used for other required messages or signals.
- the technique can be used to route dial pulse signals to telecommunications switches that require signaling according to either message-oriented or bit- oriented protocols.
- dial pulse collection in a distributed, rather than centralized, manner can reduce the amount of logic or hardware required on the channel unit cards, thereby reducing the cost of the channel unit cards.
- the collection of dial pulses can be performed in software without the use of special hardware devices, such as digital signal processors.
- FIG. 1 is a block diagram of a telecommunications system.
- FIG. 2 is a partial block diagram of a digital loop carrier.
- FIG. 3 is a block diagram of subscriber devices coupled to remote POTS cards.
- FIG. 4 is a partial block diagram of a POTS card.
- FIG. 5 is a flow chart showing steps of a method of collecting dial pulse signals.
- FIG. 6 illustrates one format of a message- oriented signal generated by a POTS card.
- a telecommunications system 2 includes a digital loop carrier (DLC) 4.
- the digital loop carrier 4 includes a central office terminal (CT) 6 coupled to one or more remote terminals (RT) 8, 10 via metallic, fiber or other suitable communication media 12.
- CT central office terminal
- RT remote terminals
- the digital loop carrier 4 acts as a delivery unit for the system 2, and delivers call control and management signals.
- Subscriber devices such as telephone service equipment 14, 16, 18, can be coupled to the central office terminal 6 and to the remote terminals 8, 10, respectively.
- the central office terminal 6 also is coupled to a local exchange carrier (LEC) network 22.
- LEC local exchange carrier
- the central office terminal 6 can be coupled to the LEC network 22 through a switch 20, such as a class 5 switch.
- switch 20 such as a class 5 switch.
- the central office terminal 6 and the remote terminals, such as terminal 8 have one or more channel unit acceptors, such as slots 26, 36, respectively.
- the slots 26, 36 accommodate channel unit cards which carry data signals to and from subscriber lines 48 and LEC network lines 46.
- the subscriber lines 48 are coupled to subscriber devices, such as the telephone 16, and the LEC network lines 46 are coupled to the LEC network 22.
- Channel unit cards convert incoming subscriber line data signals into formatted digital data and convert formatted digital data into data signals suitable for transmission over the subscriber lines.
- Different channel unit cards serve different kinds of narrowband (e.g., POTS, COIN, UVG/EWG, Four-Wire E&M, Unversal Four-Wire, Basic Rate Interface Unit) and wideband (ISDN, DS1U, T1U, ADS1U, AT1U, El, El Short
- narrowband e.g., POTS, COIN, UVG/EWG, Four-Wire E&M, Unversal Four-Wire, Basic Rate Interface Unit
- ISDN DS1U, T1U, ADS1U, AT1U, El, El Short
- the channel unit card slots 36 at the remote terminal 8 are capable of accommodating up to twenty POTS cards, 50(1) through 50(20), each of which terminates up to six subscriber lines, 48(1) through 48(120) .
- Some of the subscriber lines for example subscriber lines 48(1) and 48(6), may be coupled to rotary or other telephones 52, 54 capable of providing dial pulse signals.
- Other subscriber lines, such as subscriber line 48(120) may be coupled to a PBX 56 which converts DTMF signals received from a touchtone telephone 58 to dial pulse signals which are coupled to one of the POTS cards, such as the POTS card 50(20) .
- each of the central office terminal 6 and the remote terminal 8 also includes one or more card acceptors, such as slots 30, 40, to accommodate transmission cards.
- Transmission cards in the slots 30, 40 enable the terminals 6, 8 to communicate over the communication media 12. Different transmission cards support different communication media. Electronic Interface Level 1 (El) cards, for example, can be used to support communications over metallic media, and optical line unit cards can be used for fiber optic communications.
- El Electronic Interface Level 1
- the transmission cards in the slots 30, 40 handle the conversion between the communication medium 12 signals and electric signals that the terminals 6, 8 can understand and process.
- the central office terminal 6 and the remote terminal 8 each includes at least one Bandwidth Allocator, Processor and Timing Unit (BPT) card 28, 38.
- BPT Bandwidth Allocator, Processor and Timing Unit
- Each BPT card 28, 38 collects formatted digital signals from its respective channel unit cards in the slots 26 or 36 and multiplexes them into a time domain multiplexed (TDM) signal. The multiplexed signal then can be sent over the transmission medium 12 via the transmission cards in the slots 30 or 40, respectively.
- the BPT cards 28, 38 also receive TDM signals from their respective transmission cards.
- the BPT cards 28, 38 demultiplex the received TDM signals and route them for delivery to their respective channel unit cards in slots 26, 36.
- Respective subscriber bus interfaces 32, 42 are used to send signals between the channel unit cards in the slots 26 or 36 and their corresponding BPT cards 28 or 38.
- octal buses 34, 44 are used to send signals between the transmission cards 30 or 40 and their corresponding BPT cards 28 or 38. Further details of the BPT cards 28, 38 are described, for example, in a U.S. Patent Application (08/970,183) entitled "Telecommunications Terminal” and filed on November 14, 1997.
- the POTS card 50(1) includes a hook detector circuit 60 which can be implemented using a CODEC Subscriber Line Interface Circuit (SLIC) .
- the hook detector circuit 60 is coupled to subscriber devices, such as the telephone 52, through the subscriber line 48(1) .
- the pair of lines indicated by 48(1) in FIG. 4 represents a tip-ring pair.
- the hook detector circuit 60 also is coupled to a processor 62, such as a microcontroller or microprocessor, which includes a clock 64.
- a Motorola 68HC11 microcontroller is suitable as the processor 62.
- the clock 64 is part of the processor 62, in an alternative implementation, the clock 64 can be external to the processor 62.
- the processor 62 is coupled to a counter 66.
- the counter 66 can be implemented, for example, in software executed by the processor 62 which stores a value in random access memory (RAM) .
- the processor 62 is further coupled to the subscriber bus interface 42.
- the hook detector circuit 60 senses the state of the subscriber line current and sets an on-hook/off-hook bit which indicates the state of the subscriber line and which is sent to the processor 62.
- the on-hook/off- hook bit is set high when the current on the subscriber line is interrupted.
- the on-hook/off-hook bit is set low when the current is not interrupted.
- the processor 62 is configured to scan the on- hook/off-hook bit received from the hook detector circuit 60 as indicated by step 104. Based on the duration and number of transitions in the on-hook/off-hook bit, the processor 62 is programmed to determine whether a digit has been dialed at the telephone 52, and if so, the value of the dialed digit. In one implementation, the processor 62 is programmed to scan the on-hook/off-hook bit at a rate of approximately once every 3 milliseconds (msec) . Depending on the duration of a detected transition in the on-hook/off-hook bit, the processor 62 determines which one of several possible states is indicated by the transition. A first predetermined period can be used to check that the value of the bit is valid.
- the processor 62 interprets the bit as indicating a stable on-hook signal. If the on-hook/off-hook bit remains high for at least a second predetermined duration that is longer than the first duration, but less than a third predetermined duration, the processor 62 interprets the bit as indicating a dialed digit.
- the second predetermined duration can be, for example, approximately 100 msec.
- the processor 62 interprets the signal as indicating other states, such as hook flash or subscriber telephone on- hook states.
- the durations used by the processor 62 to interpret the on-hook/off-hook bit may vary, for example, by country or LEC network.
- processor 62 interprets a transition in the state of an on-hook/off-hook bit as a dial pulse, it increments the counter 66 by one, as indicated by step 106.
- the interpretation of the on-hook/off-hook bit by the processor 62 can be performed as part of an interrupt service software routine.
- the processor 62 also is programmed to check for the end of a sequence of one or more transitions in the state of the on-hook/off-hook bit where the sequence of transitions corresponds to a single dialed digit.
- the processor 62 checks whether a predetermined period elapses without a further change in the value stored in the counter 66. If the predetermined period, which can be on the order of approximately one second, does elapse, and the value stored in the counter has not changed again, then the processor 62 uses the value stored in the counter as the value of the dialed digit.
- the processor 62 formulates a message-oriented signal which includes the value of the dialed digit.
- a message-oriented signal which includes the value of the dialed digit.
- One suitable format for the message-oriented signal is discussed in greater detail below with respect to FIG. 6.
- the processor 62 also resets the value in the counter 66 to zero.
- FIG. 6 illustrates an exemplary format for a message-oriented signal 70 which is sent from the processor 62 in the POTS card 50(1) to the BPT card 38 in the remote terminal 8 via the subscriber bus interface 42 and which serves to indicate the value of a dialed digit.
- the message oriented signal includes seven bytes, 71-77. Two bytes 71-72 contain high level routing information.
- a third byte 73 serves to identify an activity field. Specifically, the third byte 73 identifies the signal 70 as containing the value of a dialed digit.
- a fourth byte 74 contains information identifying the physical location of the subscriber line or channel on the POTS card 50(1) .
- a fifth byte 75 identifies the value of the dialed digit.
- the sixth and seventh bytes 76-77 contains a generic identifier corresponding to the channel or subscriber line identified by the information in the fourth byte.
- the information in the sixth and seventh bytes is used by the terminals 6, 8 as an internal designator for the subscriber channel .
- Use of the foregoing format is discussed further in a U.S. Patent Application (08/996,957) entitled "Routing Call Processing Communications in a Tele-communications System” and filed December 23, 1997.
- the processor 62 on the POTS card 50(1) forwards the message-oriented signal 70 to the BPT card 38 via the subscriber bus interface 42 (step 114) .
- the signal 70 is processed and transmitted to an appropriate channel unit card at the central office terminal 6, as indicated by step 116.
- the BPT card forwards the message-oriented signal 70 as part of a TDM signal across the transmission line 12 to the central office terminal 6.
- the central office terminal 6 identifies a corresponding channel on a channel unit card in the slot 26 and passes the message-oriented signal 70 to the appropriate channel unit card.
- the channel unit card to which the signal 70 is routed is programmed to translate the information contained in the fifth byte 75 (i.e., the dialed digit) of the signal 70 into an appropriate signal or series of signals and to route the dialed digit to the LEC network 22 according to the protocol specified by the LEC network.
- the channel unit card slots 26 at the central office terminal 6 accommodate various types of channel unit cards.
- the channel unit card slots 26 accommodate an El card which routes signals from the BPT card 28 to the switch 20 according to a protocol that uses message-oriented signaling, such as the International Telecommunications Union Telecommunications standard set forth in the ITU-T Recommendation G.964, "V-Interfaces at the Digital Local Exchange (LE) - V5.1-Interface (Based on 2048 Kbit/s) for the Support of Access Network (AN) .
- the channel unit card slots 26 also accommodate channel unit cards, such as El cards, that route messages from the BPT card 28 to the switch 20 according to bit-oriented signaling, such as Channel Associated Signaling (CAS) .
- CAS Channel Associated Signaling
- the POTS cards 50(1) through 50(20) serve as the interface between the subscriber lines 48 and the BPT card 36 in the remote terminal 8 and allow the collection or counting of dial pulses to be performed in a distributed, rather than a centralized, manner. Such a distributed process of dial pulse collection can provide several advantages.
- dial pulses can be a time-consuming process which, if performed by the BPT cards 28 or 38, can tie up other important central call control functions.
- the technique described above can alleviate this problem by distributing the performance of dial pulse collection among multiple channel unit cards at the remote terminal 6.
- performing dial pulse collection in the manner described above allows message-oriented signaling to be used for messages sent between channel unit cards at the remote terminal 8 and the BPT card 38 in the remote terminal.
- the use of message-oriented signaling can free up additional bandwidth to be used for other required messages or signals.
- performing dial pulse collection as described above can reduce the amount of logic hardware required on the channel unit cards, such as digital signal processors, thereby reducing the cost of the channel unit cards .
- a POTS cards such as the POTS card 50(1)
- additional channel unit cards associated with the remote terminal 8 would translate the information contained in the fifth byte 75 (i.e., the dialed digit) of the signal 70 into an appropriate signal or series of signals and route the dialed digit, for example, to the switch 20 according to the protocol required by the switch.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Telephonic Communication Services (AREA)
- Interface Circuits In Exchanges (AREA)
Abstract
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU19249/99A AU1924999A (en) | 1997-12-23 | 1998-12-18 | Dial pulse collection in a digital loop carrier |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US99656397A | 1997-12-23 | 1997-12-23 | |
US08/996,563 | 1997-12-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999033280A1 true WO1999033280A1 (fr) | 1999-07-01 |
Family
ID=25543059
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/026873 WO1999033280A1 (fr) | 1997-12-23 | 1998-12-18 | Releve d'impulsions decimales dans une porteuse a boucle numerique |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU1924999A (fr) |
TW (1) | TW435048B (fr) |
WO (1) | WO1999033280A1 (fr) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4460806A (en) * | 1982-05-13 | 1984-07-17 | At&T Bell Laboratories | Dual tone multifrequency and dial pulse receiver |
US5263081A (en) * | 1989-11-01 | 1993-11-16 | Hubbell Incorporated | Method and apparatus for providing on-hook transmission for digital loop carrier channel units |
US5566239A (en) * | 1994-06-07 | 1996-10-15 | Teltrend, Inc. | Floating digital loop carrier telephone interface |
-
1998
- 1998-12-18 AU AU19249/99A patent/AU1924999A/en not_active Abandoned
- 1998-12-18 WO PCT/US1998/026873 patent/WO1999033280A1/fr active Application Filing
-
1999
- 1999-01-21 TW TW87121530A patent/TW435048B/zh active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4460806A (en) * | 1982-05-13 | 1984-07-17 | At&T Bell Laboratories | Dual tone multifrequency and dial pulse receiver |
US5263081A (en) * | 1989-11-01 | 1993-11-16 | Hubbell Incorporated | Method and apparatus for providing on-hook transmission for digital loop carrier channel units |
US5566239A (en) * | 1994-06-07 | 1996-10-15 | Teltrend, Inc. | Floating digital loop carrier telephone interface |
Also Published As
Publication number | Publication date |
---|---|
AU1924999A (en) | 1999-07-12 |
TW435048B (en) | 2001-05-16 |
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