Abstract:
A test system couples various ports of one or more CPE devices to components mounted in a rigid mounting system. The system can test the line card portion of the CPE devices coupled to line card interface equipment for various parameters. Variable RF attenuation in RF interface equipment can adjust power levels to/from the RF port of the CPE devices to account for close proximity and variations between different vendors and models, which are coupled via the RF interface equipment to an included CMTS. Network interface equipment tests network port performance of the CPE devices by coupling a general purpose computer thereto. Switching one of a plurality of CPE devices to be the only one tested at a time and switching an addition RENLOAD is controlled by a provisioning server based on criteria including information in a database of various parameters of the particular device being tested.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority under 35 U.S.C. 119(e) to the benefit of the filing date of Breed, U.S. provisional patent application No. 60/894,867 entitled “Method and system for testing CPE devices,” which was filed Mar. 14, 2007, and is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates, generally, to network communication devices, and, more particularly to testing multiple CPE devices that have been returned from the field due to malfunction of apparent defect. 
     BACKGROUND 
     A cable network system operator, often referred to as a multiple systems operator (“MSO) typically provides data and telephony services over a cable modem or telephony modem that operates according to the Data Over Cable Service Interface Specification (“DOCSIS”) standard and the PacketCable standard for telephony service. End users often complain that the equipment does not work properly and an MSO technician drives to a user&#39;s location, either home or office, to diagnose the problem. Often, then technician cannot determine the problem with the existing modem and replaces the existing one with a new one from his stock. 
     When the technician returns his or her replaced modems they are placed into a lot for further testing or shipment back to the manufacture for warranty purposes. The equipment that the MSO technician&#39;s typically use is cumbersome and often complicated, or is very limited in features and scenarios it can test. Thus, the MSO ultimately sends the modems back to the manufacturer who determines that there was nothing wrong with the devices. This process costs the manufacturer and the MSO time and money. Thus, there is a need in the art for a compact, simple-to-operate testing system that performs comprehensive testing of cable modems and telephony over cable modems. Furthermore, there is a need for a testing system that can evaluate modems from more than one manufacturer without the need for complex hardware modifications, such as changing jumpers on a circuit board, to accommodate the modems of a variety of manufacturers. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a system, mounted on a rigid rack mount system, for facilitating comprehensive testing of cable modems and telephony over cable modems. 
         FIG. 2  illustrates a wiring diagram for a system for facilitating comprehensive testing of cable modems and telephony over cable modems. 
         FIG. 3  illustrates a wiring diagram of RF interface equipment. 
         FIG. 4  illustrates a wiring and layout diagram for line card interface equipment 
     
    
    
     DETAILED DESCRIPTION 
     As a preliminary matter, it readily will be understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many methods, embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the following description thereof, without departing from the substance or scope of the present invention. 
     Accordingly, while the present invention has been described herein in detail in relation to preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purposes of providing a full and enabling disclosure of the invention. The disclosure is not intended nor is to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. 
     Turning now to  FIG. 1 , the figure illustrates a system  2  for performing comprehensive testing of a plurality of customer premise equipment (“CPE”) devices, such as, for example, cable modems and telephony over cable modems. System  2  is mounted to a rigid frame or housing  4 , which allows mounting of various devices and equipment that facilitates testing of the CPE devices. The equipment and devices mounted in system  4  include a cable modem termination system  6  (“CMTS”), such as, for example, a CADANT C3® sold by ARRIS Group, Inc. 
     Below CMTS  6  system  2  includes radio frequency interface (“RF”) equipment  8 , which may include RF interface port connections, such as for example, F-connectors. However, in the figure, interface F-connectors  9  are shown in a separate RF interface panel  10 . line card interface equipment  12  includes a plurality of telephone jacks, such as, for example, RJ-11 jacks, for coupling to similar telephone jacks in one or more of a plurality of CPE devices being tested. It will be appreciated that line card interface equipment  12  includes telephone jacks, but could also be mounted separate from a panel that includes the telephone jacks. 
     Network interface  14  includes a plurality of universal serial bus (“USB”) connection ports for connecting with USP connection ports of the CPE devices being tested. However, although shown separate from Ethernet interface  16 , it will be appreciated that network interface  14  could include USB connection ports as well as the Ethernet connection ports, such as, for example, RJ-45 jacks, of Ethernet interface  16 . Hereinafter, reference to network interface  14  will be understood to include reference to network interface  14  and Ethernet interface  16  unless otherwise noted. 
     Power supply panel  18  provides common household current receptacles for providing power to a plurality of CPE devices being tested. The receptacles may be individually protected and the voltage provided there from may be controllable, as is discussed later herein. 
     System also includes  2  also includes a general purpose computer running a common, user friendly, commercially available operating system. System  2  also includes a provisioning server computer, which runs a less common operating system, such as Linux, and which operates a variety of provisioning, operation and control signaling to some of the other components discussed above that are mounted in enclosure  4 . System  2  further includes a video display for displaying information and input screens of a user interface operated by general purpose computer  20 . Mounting system  4  may also include a key board tray  26  and drawer  28 . 
     Turning now to  FIG. 2 , the figure illustrates a wiring diagram for a system  2  for facilitating comprehensive testing of cable modems and telephony over cable modems. As discussed above, reference to network interface  30  includes Ethernet interface  16  and USB interface  14 . Other components shown in  FIG. 2  that were discussed in  FIG. 1  include general purpose computer  20 , provisioning server computer  22 , RF equipment  8 , line card interface equipment  12 , CMTS  6  and RF interface  10 . General purpose computer  20 , CMTS  6  and provisioning server computer  22  connect to hub  32  via network connections, preferably Ethernet connections. Hub  32  may be a common Ethernet hub as known in the art. 
     CMTS  6  couples to general purpose computer  20  via a direct connection, such as, for example, a serial bus connection using an RS-232 port. RF interface equipment  12  couples to CMTS  6  via an upstream link  34  and a downstream link  36 . These links simulate upstream and downstream links from a CMTS located at an MSO&#39;s head end facility that connect with a node on a hybrid fiber coaxial network (“HFC”). These links provide upstream and downstream RF connectivity between CMTS  6  and CPE devices being tested, which are connected to RF interface  10  via RF connections, such as coaxial cable using F-connectors. A more detailed description of RF interface equipment  8  is discussed later herein. Power is shared between RF equipment  8  and line card interface  12  via power connection  36 . Digital signals are communicated between RF equipment  8  and line card interface equipment  12  via first digital connection  38  and between the RF equipment and general purpose computer via second digital connection  40 . 
     Network signals to and from a CPE device being tested are transported through Ethernet ports mounted on interface  16  or USB ports on interface  14 . Signals transported through network interface  30  are transported to and from general purpose computer  20 , which simulates a user&#39;s personal computer connected to the Ethernet port or USB port of a CPE device being tested. 
     The digital signals communicated between LC interface equipment  12  and RF interface equipment  8  include control signals for controlling variable attenuators to regulate the RF power levels on links  34  and  36  as discussed in more detail later herein. The control signals are typically generated by provisioning server  22  and transmitted there from to general purpose computer  20  and from there over second digital link  40  and first digital link  38  to RF interface equipment  8 . The control signals are typically generated in response to power levels measured on links  34  and  36  by variable attenuators in RF interface equipment  8 . Signals representing the measured power levels are forwarded over first digital connection  38  and second digital link  40  to the provisioning server, which processes the measured power level of RF signals on links  34  and  36  and sends a control signal to regulate the power based on a comparison to a configuration table or database stored in provisioning server  22 . Thus, provisioning server  22  can regulate RF power to/from a CPE device being tested based on its manufacturer and other parameters that may be stored in the configuration database. Network interface digital links  42  and  44  couple Ethernet interface ports  16  and USB interface ports  14  to network slots on general purpose computer  20 . Thus, because both provisioning server  22  and general purpose computer  20  are coupled to hub  32 , which simulates an operator&#39;s private internet protocol network, the provisioning server can be coupled via the hub to any one of a plurality of CPE being test when either their Ethernet port or USB port, or similar digital port, is coupled to any of the network interface ports  14  or  16 . The general purpose computer so coupled simulates a user&#39;s personal computer coupled to the Ethernet or USP port of the CPE device, and can simulate any of the normal operations such a user computer would perform, such as, for examples, downloading information from the internet via the CPE device, or operating as a website server. 
     Turning now to  FIG. 3 , a wiring diagram of RF interface equipment  10 . A plurality of RF interface ports  46 , preferably F-connectors, couple links to corresponding RF interface ports on one or more CPE devices being tested. Downstream port  48  and upstream port  50  also comprise preferably F-connectors for coupling to corresponding downstream and upstream ports on CMTS  6 , shown in other figures described herein. A network of splitters  52  combines/splits signals transported between the RF interface equipment  10  and the one or more of the plurality of CPE devices being tested. Fixed attenuators  54  may also be used to reduce the strength of the signals received and transmitted from ports  50  and  48  respectively. 
     Variable attenuators  56  and  58  receive control signals via first digital connection  38 . As discussed above, first digital connection  38  connects digital communication ports of RF interface equipment  10  and LC interface equipment  12 . Provisioning server  22  generates the control signals and sends them to LC interface equipment  12  over second digital connection  40 , as discussed above in reference to  FIG. 2 . Attenuators  56  and  58  may also be capable of detecting the power level of the communication signal, or signals, present between the corresponding fixed attenuators  54 . Attenuators  56  and  58  may be capable of generating a power monitor signal based on the detected power level and then transmit the power monitor signal toward provisioning server  22  via first digital connection  38 . When provisioning server  22  receives the power monitor signal it generates a control signal that can cause the attenuation levels of variable attenuators  56  and  58  to change in response to the power monitor signal. This provides the advantage that electronic components, such as, for example, transistors, integrated circuits, etc., do not saturate because of high power levels. The output power levels of the CMTS in the downstream direction and the CPE devices in the upstream direction are designed to provide adequate signal to noise ratios over distances of several miles. Without the inherent attenuation of miles of cable to reduce these power levels, the RF output levels of the CMTS and the CPE devices in the test environment, where distances are only a few feet, are too high for the input circuitry of the CMTS in the upstream direction and the CPE devices in the downstream direction. Thus, the variable attenuators can be used to avoid saturation of the input circuitry due to too-high power levels. In addition to monitoring power levels with variable attenuators  56  and  58 , provisioning server  22  may be programmed with a configuration file that includes the nominal power output levels of CPE devices sold by various manufacturers. Thus, the provisioning server can adjust the attenuation of variable factors in variable attenuators  56  and  58  a predetermined amount by sending a control signal to the general purpose computer, which sends the control signal information from there via second digital connection  40  toward the variable attenuators to attenuate the signals passing there through. 
     Turning now to  FIG. 4 , the figure illustrates a wiring and layout diagram for line card interface equipment  12 . Line card interface ports  60  connect to jumper connector  62  on mother board  64 . Mother board  64  communicates via cable  65  with daughter card  66 . Thus, line card interface ports  60  are coupled to connection point J 12  through switching network  67 . Load circuitry  68  can be selectively coupled with telephony devices, including dial-up modems, via switch  70  between interface ports  72 , which connect to telephony devices, and line card interface ports  60 , which couple to CPE devices being tested. If switch  70  is placed into contacts broken position, which is the position shown in the figure, then no load is placed in parallel with the telephony devices coupled to interface ports  72 . If the contacts of switch  70  are made up, the extra ring load, which is simulated by the RC network  68 , sometimes referred to in the art as REN LOAD, is coupled in parallel with telephony devices coupled to ports  72  to simulate a predetermined number of traditional telephony devices (i.e., devices that have physical bell ringers, for example) coupled thereto. Thus, the test system can determine whether CPE devices being tested can generate the current and voltage necessary to ring the predetermined number of telephony devices upon receiving an incoming call.