jbreeden@netcom.UUCP (John Breeden) (10/08/90)
Rumor has it that the AMD 10BASE-T MAU chip has half size Link Integrity pulses. Can anyone confirm this? Besides being non-conformant, doesn't this shorten the distance below 100 meters? If yes, who's system level product should I worry about (who's using this chip?). Thanx in advance; -- John Robert Breeden, netcom!jbreeden@apple.com, apple!netcom!jbreeden, ATTMAIL:!jbreeden ------------------------------------------------------------------- "The nice thing about standards is that you have so many to choose from. If you don't like any of them, you just wait for next year's model."
ncpjmw@brahms.amd.com (Mike Wincn) (10/11/90)
In article <14403@netcom.UUCP> jbreeden@netcom.UUCP (John Breeden) writes: >Rumor has it that the AMD 10BASE-T MAU chip has half size Link Integrity >pulses. Can anyone confirm this? Besides being non-conformant, doesn't this >shorten the distance below 100 meters? > [...] > John Robert Breeden, In answer to your question: The TPEX (Twisted Pair Ethernet Transceiver) Link integrity pulse is not "half size", but it is not the full amplitude permitted by the transmit template shown in the 10Base-T Standard. Figure 14-10 of the Standard allows the amplitude of the Link pulse to vary from 585mVpk to 3.1vpk, when tested with a variety of loads that include a model of 100m of unshielded-twisted-pair (UTP) line. TPEX meets the template in the 10Base-T Standard for all of the required load conditions, including 100m 24GA UTP, so it is therefore "conformant". In general, if extremely poor quality cable is used, both the Link integrity pulses and transmitted packets can be degraded so badly that the 100m target distance of 10Base-T cannot be achieved, though the use of poor quality cables is not precluded by the Standard. TPEX works very well over the typical telephone cables recommended in the Standard, and certainly achieves the 100m target distance. Strictly speaking, it isn't yet proper to classify a 10Base-T device as "conformant". For this, the IEEE have to bless a "Conformance Test Document", which is basically a set of test procedures to enable all of the requirements of the Standard to be examined in a predictable and repeatable manner. Since Ian Crayford and I were directly involved in both the 10Base-T standard development and the design of the TPEX chip, plus will be involved in the generation of the Conformance Test Document, you can rest assured that current and future AMD 10Base-T networking products will be "conformant". Mike Wincn, MTS Ian Crayford TPEX Project Leader Product Planning Section Manager Network Products Division, AMD Network Products Division, AMD ncpjmw@brahms.AMD.COM (408) 749-4017 (408) 749-3156