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. 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. 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. 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 - ---------------------------------------------------------------- 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
