With reference to the statement: "The fortunate thing is that you only need to 'load' one of each type port. The other ports of the same type can use a cable connected and 'terminated'."
This is true if it is demonstrated that the addition of like ports loaded with a representative device does not increase the emissions. --- dward <dw...@atcb.com> wrote: > HI Wendy > Charles is absolutely correct - you need to be > careful here. Historically > the position of the FCC seems to have been that when > they say a port is to > have a 'load' they mean that the load is to > representative of the device. > Not just in impedance, but it is to also represent > the electrical and > mechanical characteristics of the device. This is > also the intent of ANSI > C63.4. Consequently a simple resistive load would > not be appropriate. > > Also, realistically speaking, the only way to 'load' > a port is to put a real > device on the port (i.e. a parallel port serial port > and USB port device > etc.). Please note that the ITE section of ANSI > C63.4 states "When a PC is > the EUT and also the host, the minimum functional > interface (I/O) ports that > shall be populated by attaching cables, which are > terminated in a typical > load of actual usage, include serial, parallel, and > USB, where such ports > are available." Please note the 'load OF ACTUAL > USAGE" statement. The > fortunate thing is that you only need to 'load' one > of each type port. The > other ports of the same type can use a cable > connected and 'terminated'. > > Thanks > > Dennis Ward > Director of Engineering > American TCB > Certification Resource for the Wireless Industry > www.atcb.com > 703-847-4700 fax 703-847-6888 > direct - 703-880-4841 > > NOTICE: This E-Mail message and any attachment may > contain privileged or > company proprietary information. If you received > this message in error, > please return to the sender. > > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] > On Behalf Of Grasso, > Charles > Sent: 03/20/2008 10:17 AM > To: wendy...@labone.com.sg; emc-p...@ieee.org > Subject: RE: Terminations for PC during emission > measurements > > Wendy - I strongly recommend you research this more > thoroughly. > PCs have special test requirements (such as active > I/O!) that you > will need to accommodate. > > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] > On Behalf Of > wendy...@labone.com.sg > Sent: Tuesday, March 18, 2008 5:49 PM > To: emc-p...@ieee.org > Subject: Terminations for PC during emission > measurements > > Dear All, > ANSI C63.4 states that when testing a computer, its > interface I/O are to > be terminated by peripheral or load. > I am trying to find out the load impedance for > parallel, serial, USB, > etc- ports commonly found on a PC. My intention is > to terminate the > ports with load rather than actual peripheral to > save cost. If someone > has a 'quicker' and 'cheaper' way to do this, please > enlighten me. > Thank you in advance. > Regards, Wendy Nya > > - > > This message is from the IEEE Product Safety > Engineering Society > emc-pstc discussion list. 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Website: > http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to > emc-p...@ieee.org > > Instructions: > http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas emcp...@ptcnh.net > Mike Cantwell mcantw...@ieee.org > > For policy questions, send mail to: > > Jim Bacher: j.bac...@ieee.org > David Heald: emc-p...@daveheald.com > > All emc-pstc postings are archived and searchable on > the web at: > > http://www.ieeecommunities.org/emc-pstc > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
