WO1998046042A1 - Carrier card interface to a daughter board - Google Patents
Carrier card interface to a daughter board Download PDFInfo
- Publication number
- WO1998046042A1 WO1998046042A1 PCT/US1998/007281 US9807281W WO9846042A1 WO 1998046042 A1 WO1998046042 A1 WO 1998046042A1 US 9807281 W US9807281 W US 9807281W WO 9846042 A1 WO9846042 A1 WO 9846042A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- daughter board
- carrier card
- echo
- set forth
- board
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L49/00—Packet switching elements
- H04L49/90—Buffering arrangements
- H04L49/9063—Intermediate storage in different physical parts of a node or terminal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L49/00—Packet switching elements
- H04L49/90—Buffering arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/002—Applications of echo suppressors or cancellers in telephonic connections
Definitions
- This invention is related in general to the field of electronic circuits, and more particularly, to a carrier card interface to a daughter board.
- the distributed telecommunications switch system includes a service unit (SU) coupled to one or more delivery units (DUs) .
- the delivery units provide the switching function and network interfaces to transmit the call information to other delivery units or other wireless or wire line networks.
- the service unit controls and directs each delivery unit in the switching of call information from origination to destination.
- the distributed telecommunications switching system can support multiple delivery units that provide a variety of services, including broadband interfacing, cable applications, telephony interfacing, and personal communications services .
- an interface to a daughter board includes a carrier card, a board interface connector residing on the carrier card operable to couple the daughter board to the carrier card, and a control message bus coupled between the carrier card and the daughter board. Further, the interface includes an on board controller residing on the carrier card which is in communication with the daughter board by receiving and transmitting control messages transported on the control message bus.
- the interface also includes a data bus adapted for transporting data between the carrier card and the daughter board, and a data bus interface coupled to the on board controller operable to transport a plurality of channels of telecommunications data to the daughter board via the data bus under the control of the on board controller.
- a method of performing echo cancellation on an OC-N signal includes the steps of receiving, at a carrier card, a pulse code modulated telecommunications signal over a bus control module, and transmitting the pulse code modulated telecommunications signal to a daughter board over a serial data bus under the control of control messages transmitted between the carrier card and the daughter board. Echo cancellation is performed on the pulse code modulated telecommunications signal to generate an echo canceled signal, the echo canceled signal is transmitted over the serial data bus to the carrier card under the control of control messages transmitted between the carrier card and the daughter board.
- a technical advantage of the present invention is the provision of an interface that will accept a third party manufactured digital signal processing board and connecting it into a DSO data stream on a call-by-call basis in a switching system that operates at the OC-N level.
- FIGURE 1 is a simplified block diagram of a distributed telecommunications switching system (multi services platform) ;
- FIGURE 2 is a diagram of the high level OC3 architecture;
- FIGURE 3 is a block diagram of the echo canceler card according to the teachings of the present invention.
- FIGURE 4 is a diagram of an inheritance hierarchy of object oriented classes.
- the purpose of the echo canceler interface is to provide an interface between a third party echo canceler daughter board and an OC3 carrier card such that the daughter board can operate properly in the distributed telecommunications switching system described in Self et al .
- FIGURE 1 is a simplified block diagram of a distributed telecommunications switching system 10 described in detail in Self et al .
- Distributed telecommunications switching system 10 includes a service unit 12 coupled to one or more delivery units 14.
- Delivery units 14 provide the switching function and network interfaces to transmit call information to other delivery units 14 or other wireless or wire line networks.
- Service unit 12 controls and directs each delivery unit 14 in the switching of call information from origination to destination.
- distributed telecommunications switching system 10 may include an OC3 delivery unit 20, a service unit 22, and a DSl delivery unit 24, as shown in FIGURE 1.
- DSl delivery unit 24 terminates DSl level electrical signals
- OC3 delivery unit 20 terminates OC-3 level optical signals and converts them to DSO signals that can be connected to matrices 30 in DSl delivery unit 24.
- external DSl echo cancelers (not shown) are coupled to DSl delivery unit 24 to provide the echo cancellation function.
- OC3 delivery unit 20 it has been recognized that external echo cancelers operating directly on DSl or DSO level signals are not a viable solution. Therefore, echo cancelers should be integrated into OC3 delivery unit 20 in order to have access to DSO level signals.
- OC3 delivery unit 20 of the present invention includes an OC3 shelf 32 that has redundant optical terminating modules (OTM) 34 receiving optical signals, such as SONET OC-3 signals, from the public switched network (PSN) and converting them to electrical signals, such as STS-1 level signals, which may contain overhead data portions that have been formatted in a proprietary manner.
- the STS-1 signals are then transmitted to and received by synchronous transport signal modules (STSM) 36.
- STSM synchronous transport signal modules
- Synchronous transport signal modules 36 are coupled to or plugged into a bus control module (BCM) 38 which is extended to an echo shelf 70.
- Bus control module 38 is also coupled to a number of application circuits, which may include a matrix interface circuit (MTXI) 40, tone recognition circuit 42, and high speed line trunk processor (HLTP) 44, to transmit telecommunications data thereto.
- MTXI matrix interface circuit
- HLTP high speed line trunk processor
- Echo shelf 70 includes one or more echo canceler cards 72 coupled to bus control module 38. Each echo canceler card 72 is operable to receive all 2,016 DSO channels in an OC-3 signal through bus control module 38. Echo canceler cards 72 may include one or more spare cards 73 for redundancy. It may be noted that all components in OC3 delivery unit 20, except echo canceler cards, include an active and a standby unit (as represented by the shadow blocks) for system redundancy and signal integrity. To provide the flexibility of enabling third party echo cancelers to function in echo canceler cards 72, a carrier card 74 is provided to host a third party echo canceler daughter board 76 as shown in FIGURE 3.
- Carrier card 74 supports a standard PCI (peripheral component interconnect) interface, such as CompactPCITM, for communication between an on board controller (OBC) 80 residing on carrier card 74 and a daughter board 76 coupled thereto via a PCI bridge or control message bus 84.
- On board controller 80 includes one or more microprocessor 81 which communicates with a microprocessor 77 residing on daughter board 76 using messages.
- Carrier card 74 also supports a second interface, such as SCSA (signal computing system architecture) , for the transport of isochronous data on an SCSA bus 86 coupled between a system bus interface (BIF) 82 on carrier card 74 and daughter board 76.
- System bus interface 82 provides the conversion between the internal system redundant buses and the SCSA interface.
- SCSA bus 86 includes a data bus for transporting time division multiplexed (TDM) pulse code modulation (PCM) data in a bit serial manner.
- TDM time division multiplexed
- PCM pulse code modulation
- the SCSA data bus serial stream is divided into 1024 8.192 MHz divisions or frames. Each frame is thus 125 ⁇ s long.
- the SCSA data bus is a serial 16-bit wide bus, there are 16 PCM samples transmitted at any one time. During the 8 time divisions which constitute a serial data (SD) unit, 16 PCM samples are transmitted.
- SD unit is defined as an integral, serial, consecutive 8-bit group of time divisions on the 16-bit data bus.
- the first 8-bit group following a frame sync is designated as SD unit 0, the second is designated as SD unit 1, etc.
- At least one echo canceler or signal processing circuit or device may reside on daughter board 76 mounted on carrier card 74. In the present embodiment, a minimum of 288 echo cancelers and a maximum of 384 echo cancelers may be supported by each daughter board 76.
- the CompactPCI' IM interface between echo canceler daughter board 76 and carrier card 74 specifies all mechanical characteristics of daughter board 76, such as size and connectors.
- the purpose of the PCI Interface is to provide an industry standard interface between on board controller 80 and daughter board 76.
- the PCI Interface is used for processor communications between on board controller 80 and daughter board microprocessor 77.
- a message-based interface may be defined that provides full OAM&P (operations, administration, maintenance and provisioning) support for daughter board 76 as well as call processing interface that allows echo cancelers 83 to be used on a call-by-call basis.
- the SCSA interface provides an industry standard interface between daughter board 76 and system bus interface 82 for transporting PCM data.
- Support for up to 768 DSO channels between daughter board 76 and system bus interface 82 may be provided, which allows daughter board 76 to support up to 384 echo cancelers 83, for example.
- Daughter board 76 may be configured to support a predetermined minimum number of echo cancelers and up to a predetermined maximum number of echo cancelers 83.
- the interface between daughter board 76 and on board controller 80 includes a set of messages that incorporates the use of echo cancelers 83 in a call.
- the echo canceler parameters are communicated to an echo canceler 83 on a call-by-call basis.
- a functional description of this interface is provided below by defining the object classes and the operations to be supported on those object classes.
- a point-to-point connection is provided between daughter board 76 and on board controller 80. From the on board controller's point of view, daughter board 76 provides an echo canceler service that can be connected to a call.
- the software interface to daughter board 76 supports this capability. If daughter board 76 cannot support this capability, it informs on board controller 80 so that subsequent requests for service to that daughter board are rejected. Distributed telecommunications switching system 10 may then request service from other functioning echo cancelers 83.
- Faults on carrier card 74 may be of three types:
- Faults isolated to daughter board 76 may treat all of the above faults in the same manner. A notification is generated and, if the fault is isolated to daughter board 76, the notification includes this fact. On board controller 80 may not test daughter board 76, so that fault detection of daughter board 76 is the responsibility of the daughter board itself. On board controller 80 may only routinely verify that it can properly communicate with daughter board 76. If communication with daughter board 76 is lost, carrier card 74 is removed from service and the system attempts to replace the function of the faulty card by using the spare card. Additionally, on board controller 80 may periodically reset daughter board 76 via the PCI Interface until communication is re-established.
- Daughter board 76 may detect a loss of communication with on board controller 80. However, it may not initiate any type of recovery action which may disturb echo canceler cards 83 currently in use. From the distributed telecommunications switching system point of view, carrier card 74 and its daughter board 76 are a single entity. If the distributed telecommunications system craft requests removal of carrier card 74, then on board controller 80 informs daughter board 76 of this status change.
- Echo cancelers 83 are assigned on a call-by-call basis. On board controller 80 may request an echo canceler 83 from daughter board 76 by issuing a CONNECT command message, for example. This command allows on board controller 80 to specify a particular echo canceler 83.
- All the attributes of echo canceler 83 associated with processing the call may be included in the CONNECT command.
- daughter board 76 When daughter board 76 receives the CONNECT command it initializes the echo canceler with the specified parameters. Once connected, daughter board 76 may send an acknowledgment back to on board controller 80 with an identifier of the echo canceler within a predetermined time period. If an echo canceler 83 cannot be connected due to failure, daughter board 76 responds accordingly. If daughter board 76 has a partial failure where only a few echo cancelers failed, daughter board 76 may automatically switch the calls to available echo cancelers on the same board 76 and notify on board controller 80 for each call that has been assigned a new echo canceler 83. If daughter board 76 cannot switch the call to an idle echo canceler 83, it may place the echo canceler in a bypass mode and notify on board controller 80 for each affected call.
- Object classes are defined to specify the interface between daughter board 76 and on board controller 80.
- On board controller 80 represents the managing system while daughter board 76 represents the managed system.
- On board controller 80 is the manager while daughter board 76 serves the agent role.
- ecDaughterBoard object class 90 is a class of managed objects that represent daughter board 76 from the perspective of on board controller 80. A single instance of this object class is created by daughter board 76 at daughter board initialization time.
- Daughter board 76 generates an object creation notification message after the instance of the ecDaughterBoard object is created and sends this notification to on board controller 80. The object creation notification message is used to notify on board controller 80 that daughter card 76 has been initialized and how many echo cancelers 83 it supports.
- a state change notification message is used to inform on board controller 80 of a state change of daughter board 76.
- a state change may be due to an internal failure of the daughter board 76 (operational state) .
- An operational state of daughter board 76 informs on board controller 80 whether daughter board 76 is capable of providing echo cancellation services.
- An administrative state is used to support the removal and restoration of the echo canceler card from distributed telecommunications switching system 10. If an echo canceler card is to be removed from service by the distributed telecommunications switching system 10, on board controller 80 issues a SET command to the administrative state attribute. On board controller 80 may issue a GET command to obtain the operational or administrative state of daughter board 76.
- ecSoftware class 92 is a class of managed objects which represents the software on daughter board 76 as viewed from the perspective of on board controller 80. An instance of this object class is inherently created by daughter board 76 during initialization. An object creation notification is not generated or sent when this object is created. Class ecSoftware generates the download request notification if the underlying software represented by this object does not exist. At initialization, ecSoftware object determines if a valid load of software is present on all processors on daughter board 76. If this condition is not true, ecSoftware object generates the download request notification. If the software code is not downloaded within a predetermined time, ecSoftware object causes daughter board 76 to restart the initialization sequence.
- daughter board 76 determines that the underlying code represented by the ecSoftware object is present, it creates an instance of ecDaughterBoard object class 90. Code is downloaded via the ecSoftware object utilizing a downloadChunk action by iteratively invoking it until all code is downloaded to daughter board 76. Once the code has been downloaded, daughter board 76 verifies its checksum and continues to create an instance of ecSoftware managed object 92. If the checksum verification fails, a checksumFailure notification is generated, and the code represented by the created object is deleted. The initialization sequence is then restarted to download the software. Object ecSoftware will routinely verify its checksum after it has been created.
- ecCircuit class 94 is a class of managed objects that represents the individual echo canceler circuits 83 on daughter board 76 from the perspective of on board controller 80. An instance of this object class is inherently created by on board controller 80 for every echo canceler circuit 83 on daughter board 76. Create notifications are not generated for this object.
- Object class ecCircuit 94 is used to initialize the echo canceler parameters. These parameters are provisioned with respect to a DSO level signal. When a call is made on a DSO signal that needs echo cancellation, the parameters are downloaded to the object instance of the echo canceler that will provide this function as part of a CONNECT action or command.
- the attributes of ecCircuit object are set by carrier card 74 via the CONNECT command.
- the GET/SET commands on each attribute can also be used to change or read the value of the attribute.
- the attributes for an echo canceler 83 are valid only when the particular echo canceler is in use.
- An operationalState attribute is maintained by ecDaughterCard object 90 and indicates if the echo canceler circuit is operational.
- a usageState attribute indicates if a call is in progress on the echo canceler. This state attribute is normally idle except when a CONNECT or loopback request is received.
- a stateChange notification is used to indicate a change in the operational state of the echo canceler. This notification indicates whether the call was placed in the bypass mode.
- Daughter board 76 honors CONNECT requests except when it determines that the echo canceler failed or cannot provide the service for some reason. If daughter board 76 determines that the echo canceler is currently busy, it honors the CONNECT request but indicates this condition in the CONNECT response.
- ecDaughterCard This attribute is used to describe the administrative state of daughter board 76 and echo canceler circuits 83.
- administrativeState This attribute is used to describe the administrative state of daughter board 76 and echo canceler circuits 83.
- unlocked daughter board 76 is allowed to perform its functions.
- daughter board 76 may not support ACTION commands such as connectEC, disconnectEC, loopback, and releaseLoopback. This attribute is based on recommendation X.721.
- availabilityStatus This attribute is used to describe the availability status of daughter board 76. The purpose of this attribute is to indicate to on board controller 80 when daughter board 76 is partially disabled. That is, daughter board 76 has a problem that reduces its capability. This attribute is based on recommendation X.721.
- echoReturnLoss This attribute is used to indicate to the echo canceler what value it should use for the echo return loss (ERL) for this call.
- toneDisablerMode This attribute is used to indicate to the echo canceler what mode the tone disabler should be set to for this call.
- suppressionThresholdMode This attribute is used to indicate to the echo canceler what type of suppression threshold to use for the call.
- • suppressionThresholdValue - This attribute is used to indicate to the echo canceler what the threshold value should be for this call. This attribute is only applicable when the suppressionThresholdMode is set to the fixed- mode .
- tailSizeAutoIncrement - This attribute is used to indicate to the echo canceler whether or not the echo canceler should automatically select the optimum tail size.
- ToneDisablerMessageReport - This attribute is used to indicate to the echo canceler if it should generate a message to the echo canceler management system when the echo canceler detects a valid disabler tone.
- • h VendorName - This attribute is used to identify the vendor of the carrier card and is used for display purposes only.
- comfortNoiseLevel This attributes specifies the comfort noise level. This attribute is only applicable when the non-linear processor is set to OnWithComfortNoise.
- • dataCollectionReport - This attribute is used to indicate to the echo canceler if it should generate a message to the carrier card with the echo canceler data information for that call.
- objectCreation This notification is required to report to on board controller 80 that an object has been created. From the point of the on board controller, only the ecDaughterCard object 90 supports this notification. The notification informs on board controller 80 that the daughter board 76 is up and running.
- toneDisablerReport - This notification is used to report to carrier card 74 when an echo canceler circuit 83 is disabled because it has received a valid tone disabler message. A specific flag may be set to enable this notification.
- • dataCollectionReport - This notification is used to report echo canceler data, such as ERL level, transmit power, and receive power, etc. to carrier card 74.
- a specific flag may be set to enable this notification.
- checksumFailure This notification is used to report to carrier card 74 that daughter board detected a checksum failure on its software.
- the following is a list of exemplary actions that may take place:
- disConnectEc The disConnectEc service is sent from the on board controller to the daughter board 76 to disable echo cancellation on the circuit. No information is required in the response.
- the response shall be provided within a predetermined amount of time, for example 5 ms .
- loopbackEC The loopback service is sent from carrier card 74 to daughter board 76 to loopback the channels. No information is required in the response.
- the response shall be provided within a predetermined amount of time, for example 5 ms .
- releaseLoopbackEC - This service is sent from carrier card 74 to daughter board 76 to release the loopback of the channels. No information is required in the response. The response shall be provided within a predetermined amount of time, for example 5 ms .
- test - The test service is sent from carrier card
- the SCSA bus contains 2048 channels which can be configured to transport PCM speech samples to and from echo canceler daughter card 76.
- Daughter card 76 may handle 288 echo canceler channels, for example.
- the SCSA bus time slots are fixed for each echo channel.
- the SCSA time slots are assigned to the echo channels according to a predetermined assignment specification.
- Host carrier card 74 sends control messages to daughter board 76 over PCI bridge 84 to control the operations of the echo cancelers. The following is a description of selected control messages.
- the control message set may include a CONNECT message, which includes certain information elements, such as: Message Identification, Channel Identification, PCM Encoding, Maximum Tail Delay, Automatic Tail Delay Increment, Automatic Tail Delay Increment Control, ITU Mode, Tone Disabler Mode, Tone Disabler Message Reporting Control, Switched 56K Mode, Re-Enable Mode, NLP Operating Parameters, NLP Control, Noise Matching Operating Parameters, Noise Matching Control, Minimum ERL Level, and Alarm Reporting Control.
- Host carrier card 74 sends this message to echo canceler daughter board 76 (ECDB) to set the channel configuration parameters to a provisional parameters set by the system.
- ECDB echo canceler daughter board 76
- the set channel configuration parameter message is sent after initialization and when the provisional state is changed by craft personnel. These parameters over-write the default parameter values.
- the control message set may also include a second type of CONNECT message, which may include most of the same information elements as the set channel configuration parameter message.
- Host carrier card 74 sends this message to daughter board 76 to set the echo canceler parameters and enable echo cancellation at the same time. This can be used if the echo canceler channel parameters are changed on call-by-call basis.
- the control message set may also include a third type of CONNECT message, which merely enables a specific echo canceler channel specified in the message.
- the host carrier card 74 send this message to ECDB 76 to enable echo canceler channel for normal echo cancellation processing.
- the echo canceler performs its function until it is told by the host to stop processing.
- the control message set may also include a fourth type of CONNECT message that contains the Channel Identification and the Call Type information elements.
- the host carrier card 74 sends this message to ECDB 76 to enable the specified echo canceler channel on a call that is already established.
- the echo canceler performs the normal function depending on the call type.
- the echo canceler performs its function until it is told by the host to stop processing. This message is used when an echo channel is switched in during a call which is in progress.
- a DISCONNECT message may also be included in the control message set to disable echo canceler processing.
- the echo canceler in this mode performs bypass on both receive and transmit direction.
- the control message set may also include an ECDB initialization request message.
- Host carrier card 74 sends this message to ECDB 76 to request that all echo channels be initialized to their default (power-up) parameter values. Once all channels are restored an ECDB initialization complete message is sent to the host indicating successful completion of the initialization sequence.
- the control message set may also include an ECDB ID inquiry message.
- Host carrier card 74 may send this message to ECDB 76 during initialization to know what type of daughter card it is communicating with. This is used for configuration control.
- the ECDB should respond to this message at any time by returning an ECDB ID report message.
- the ECDB ID report message includes the revision ID of the echo canceler daughter card.
- ECDB 76 may send a predetermined key that identifies it as a valid card for the system. If the host does not recognize the key, then the daughter board is not an authorized card and will be rejected. It may be seen that messages are used to request actions to be taken (carrier card to ECDB) and notifications of events which have occurred (ECDB to carrier card) . Parameters are passed in these messages via object attributes. Exemplary attributes, actions and notifications are described above.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Telephonic Communication Services (AREA)
- Communication Control (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP54317198A JP2002511960A (en) | 1997-04-10 | 1998-04-09 | Carrier card interface to daughter board |
EP98918105A EP0974241A1 (en) | 1997-04-10 | 1998-04-09 | Carrier card interface to a daughter board |
AU71094/98A AU7109498A (en) | 1997-04-10 | 1998-04-09 | Carrier card interface to a daughter board |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US4346297P | 1997-04-10 | 1997-04-10 | |
US60/043,462 | 1997-04-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998046042A1 true WO1998046042A1 (en) | 1998-10-15 |
Family
ID=21927297
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1998/007281 WO1998046042A1 (en) | 1997-04-10 | 1998-04-09 | Carrier card interface to a daughter board |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0974241A1 (en) |
JP (1) | JP2002511960A (en) |
AU (1) | AU7109498A (en) |
WO (1) | WO1998046042A1 (en) |
ZA (1) | ZA983051B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10863895B2 (en) | 2015-05-27 | 2020-12-15 | The Regents Of The University Of California | Terahertz endoscopy through laser-driven terahertz sources and detectors |
US11112305B2 (en) | 2012-01-23 | 2021-09-07 | The Regents Of The University Of California | Photoconductive detector device with plasmonic electrodes |
US11249017B2 (en) | 2017-04-20 | 2022-02-15 | The Regents Of The University Of California | Systems and methods for high frequency nanoscopy |
US11906424B2 (en) | 2019-10-01 | 2024-02-20 | The Regents Of The University Of California | Method for identifying chemical and structural variations through terahertz time-domain spectroscopy |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4747896B2 (en) * | 2006-03-17 | 2011-08-17 | ソニー株式会社 | Information processing apparatus and method, and program |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0353102A2 (en) * | 1988-07-29 | 1990-01-31 | Teknekron Infoswitch Corporation | Automatic call distribution (ACD) switching system having distributed processing capability |
WO1993026113A1 (en) * | 1992-06-15 | 1993-12-23 | British Telecommunications Public Limited Company | Service platform |
-
1998
- 1998-04-09 EP EP98918105A patent/EP0974241A1/en not_active Withdrawn
- 1998-04-09 JP JP54317198A patent/JP2002511960A/en active Pending
- 1998-04-09 WO PCT/US1998/007281 patent/WO1998046042A1/en not_active Application Discontinuation
- 1998-04-09 ZA ZA9803051A patent/ZA983051B/en unknown
- 1998-04-09 AU AU71094/98A patent/AU7109498A/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0353102A2 (en) * | 1988-07-29 | 1990-01-31 | Teknekron Infoswitch Corporation | Automatic call distribution (ACD) switching system having distributed processing capability |
WO1993026113A1 (en) * | 1992-06-15 | 1993-12-23 | British Telecommunications Public Limited Company | Service platform |
Non-Patent Citations (3)
Title |
---|
ERIKSSON A ET AL: "ERICSSON ECHO CANCELLERS A KEY TO IMPROVED SPEECH QUALITY", ERICSSON REVIEW, vol. 73, no. 1, 1 January 1996 (1996-01-01), pages 25 - 33, XP000584598 * |
FLEGG R: "COMPUTER TELEPHONY ARCHITECTURES: MVIP, H-MVIP, AND SCBUS", IEEE COMMUNICATIONS MAGAZINE, vol. 34, no. 4, 1 April 1996 (1996-04-01), pages 60 - 64, XP000586072 * |
HAGG U ET AL: "AXE HARDWARE EVOLUTION", ERICSSON REVIEW, vol. 74, no. 2, 1997, pages 52 - 61, XP000656978 * |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11112305B2 (en) | 2012-01-23 | 2021-09-07 | The Regents Of The University Of California | Photoconductive detector device with plasmonic electrodes |
US11231318B2 (en) | 2012-01-23 | 2022-01-25 | The Regents Of The University Of California | Photoconductive detector device with plasmonic electrodes |
US10863895B2 (en) | 2015-05-27 | 2020-12-15 | The Regents Of The University Of California | Terahertz endoscopy through laser-driven terahertz sources and detectors |
US11249017B2 (en) | 2017-04-20 | 2022-02-15 | The Regents Of The University Of California | Systems and methods for high frequency nanoscopy |
US11906424B2 (en) | 2019-10-01 | 2024-02-20 | The Regents Of The University Of California | Method for identifying chemical and structural variations through terahertz time-domain spectroscopy |
Also Published As
Publication number | Publication date |
---|---|
EP0974241A1 (en) | 2000-01-26 |
JP2002511960A (en) | 2002-04-16 |
ZA983051B (en) | 1999-10-11 |
AU7109498A (en) | 1998-10-30 |
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