Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
1999-10-05
2003-09-02
Chin, Wellington (Department: 2664)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
C370S537000
Reexamination Certificate
active
06614811
ABSTRACT:
The present invention relates to telecommunication access devices and in particular, the present invention relates to a modular device that is configurable to achieve any of several different types of functionality and that has improved circuitry and mechanical features.
BACKGROUND OF THE INVENTION
With the increased use of telecommunications circuits such as telephone lines to communicate video and data within computer networks, data between facsimile machines, and other telecommunication applications, there is an increased need for various telecommunication devices to perform the necessary telephone switching, multiplexing of signals, interfacing, converting between various data formats, control of other equipment, and so forth. As the amount of data passed between various users increases, even greater demands are placed on such telecommunication equipment.
One type of telecommunication device currently in use is commonly known as a channel bank. A channel bank is a muliplexer which assigns time slots to multiple relatively slower-speed voice or data channels in a single relatively higher-speed link. In a typical situation, a channel bank may multiplex up to 24 different DS-0 channels, each of which represent a single voice conversation digitized at 64 kilobits per second. The 24 DS-0 channels together are multiplexed to create one DS-1 channel passed over a T-1 data link at 1.544 megabits per second. An example of such equipment is sold by the assignee of the present invention, Carrier Access Corporation, as the Access Bank I, and described in part in U.S. Pat. No. 5,881,148. This device includes a single Line Interface Unit card and a pair of channel line cards, with each channel line card handling twelve DS-0 channels.
Another type of telecommunication device is generally known as an integrated access device. Such devices support voice, data, and video information streams over a single, high capacity circuit. An example of an integrated access device is sold by the assignee of the present invention, Carrier Access Corporation, as the Access Bank II.
Taking the example of a start-up business that may begin with a few phone lines. As the number of phone lines grows, it may be necessary to add more channel banks. Eventually, it will be desired to have additional lines for fax and computer traffic, and more or different equipment may be necessary. As the business grows in size additional telephones may be needed and the small business may elect to utilize a private branch exchange or PBX. A PBX allows for a greater number of internal telephones and telephone lines than there are outside lines. The business may eventually acquire a T-1 line to carry all or portions of its voice and data traffic. A channel bank may be purchased to connect the telephone lines to the T-1 line. An integrated access device may later be purchased to route data to external routers and voice lines to an internal PBX. As the company continues to grow, its voice and data needs do as well, and additional equipment will continually have to be purchased. There is a need for telecommunication equipment that is flexible enough so that the user can configure and use the device for any of a variety of applications.
Turning now to issues arising within telecommunication devices, there are many such devices that are configured in a master/slave relationship. These may include devices with a controller card that controls the function of each of two or more other circuit cards. These circuit cards may process relatively lower speed data than the data processed on the controller card, for example. This control by the controller card of the circuit cards has typically taken place over large address and data buses connected to each circuit card. In fact, in many cases, there are dedicated buses between each circuit card and the controller. Of course, this control data passed between the circuit cards and the controller card is in addition to the non-control data passed between the circuit cards and the controller cards, such as the voice channels in the telephone network and the data channels between computers in a computer network.
Because of all the control data and non-control data passed between circuit cards and controller cards, there is a need for a great deal of input/output resources on the controller card and the circuit cards. Typically, these resources, such as external connectors, are located on the front edge or back edge of the controller and circuit cards. Unfortunately, the front edge of such cards is also the location where mechanical devices are typically located for fastening the controller cards and circuit cards within the housing or card cage of the telecommunication device.
Certain telecommunication devices include the capability for circuit cards therewithin to be removed and inserted while the device is operating, or “hot-swapped”. In such systems, it is desirable to have a reliable means to sense that a card is present in a particular slot in a telecommunication device versus whether a card is missing from that slot. In addition, it is desirable to sense that the right type of card has been inserted in that slot. It is then desirable to be able to efficiently communicate with the circuit cards.
Another issue, in the case of a controller card that communicates with voice cards such as FXS or FXO cards, is that it is necessary to pass signaling information between the controller and voice cards for various phone line states, such as ringing, off hook, and so forth. This needs to be done with as little delay and as near to real time as is possible. Fortunately, the number of bits of information that needs to be sent is relatively small. Also, there is a need to pass relatively larger amounts of control and status information between the controller and voice cards. Fortunately, this information is not real time and can be sent much more slowly than the signaling information. Typically, because of the different demands of passing these two different types of information, different buses have been used for each.
It is also desirable to develop improved circuitry for ringer circuits and for circuits for monitoring the condition of back-up batteries associated with telecommunication devices.
Lastly, it is desired to improve on the prior art schemes for latching circuit cards into circuit card housings. Typically this has been handled with pivotally-mounted retaining latches (also known as PCB extractors) that are mounted to a front edge of the circuit card and can be engaged with mating surfaces on the housing. Unfortunately, such approaches have some drawbacks. First of all, for high volume cards the cost of the these retaining latches can be excessive. Second, the latches typically mount to the front edge and take up precious real estate where I/O and indicators need to be located. Third, the plastic latches provide no grounding or EMI protection. Fourth, the design requires a two-handed removal or insertion operation. Fifth, multi-piece assemblies such as the latches and the required retaining pins require secondary assembly operations and pose reliability concerns.
It is against this background, and the desire to solve the problems of and improve on the prior art, that the present invention has been developed.
SUMMARY OF THE INVENTION
The present invention is directed to a telecommunication device including a controller circuit, a connector electrically connected to the controller circuit, and a plurality of telecommunication circuits electrically connectable to the connector. Each telecommunication circuit receives control and status information from the controller circuit via a first TDM signal passed through the connector from the controller to the telecommunication circuits and transmits control and status information to the controller circuit via a second TDM signal passed through the connector from the telecommunication circuits to the controller. Each telecommunication circuit determines where in the first TDM signal to find information related to that telecommunication circuit and wher
Alaimo S. Christopher
Cambier Craig Steven
Clark Phillip D.
English Susan I.
Millican Mark
Carrier Access Corporation
Chin Wellington
Holland & Hart LLP
Schultz William
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