Talk:Fast Ethernet

200 Mb Ethernet
The intro claims full-duplex FE is called "200 Mb Ethernet". I'm not disputing that bidirectional bandwidth is 200 Mb but I've never heard anyone claim that FE should be called 200 Mb. I plan to remove the statement unless someone steps up to substantiate it. --Kvng (talk) 16:01, 5 May 2010 (UTC)

Back when 100Mb Ethernet was all "new and awseome", manufacturers actually advertised with the bidirectional 200Mb. I remember, when buying network cards 10 years ago, the packaging always said "200Mb speed in duplex mode". So it would be correct to say it was advertised as supporting 200Mb in order to appear faster. 200Mb was not an official name, just for the ads. Similar to hard disks, where they advertise with GB instead of GiB. --unregistered 2:26, 10 June 2010 (UTC) —Preceding unsigned comment added by 118.92.98.119 (talk)

100BASE-T1
added coverage of 100BASE-T1. Thanks for that. Is this the IEEE version of BroadR-Reach? ~Kvng (talk) 13:43, 5 October 2016 (UTC)


 * Pretty hard to find, but I just found a source - will be added in a moment. --Zac67 (talk) 18:11, 6 October 2016 (UTC)
 * "3 bits per symbol (PAM3)". Is that true? Ternary signal says that the 3 in PAM3 means 3 signal states, not 3 bits.--Heron (talk) 13:53, 15 July 2019 (UTC)
 * You're right that it didn't make sense that way. Each 3-bit symbol is transmitted as a pair of ternary PAM3-codes (three voltage levels). Check Clause 96.3.3.1. --Zac67 (talk) 16:44, 15 July 2019 (UTC)

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Semantics of 100BASE-T
From IEEE 802.3-2018 Section 21 "Introduction to 100 Mb/s baseband networks, type 100BASE-T": "100BASE-T uses the existing IEEE 802.3 MAC layer interface, connected through a Media-Independent Interface layer to a Physical Layer entity (PHY) sublayer such as 100BASE-T4, 100BASE-TX, or 100BASE-FX."

Notice the that standard explicitly mentions "100BASE-FX"; in fact, if you read carefully, you will see that the 100BASE-T section doesn't say anything about twisted pair as a medium or the PMD (Physical Medium Dependent) subsystem of the PHY. This is very confusing, because the same standard states in Section 1.2.3 "Physical Layer and media notation": "...additional distinctions are “T” for twisted pair...". Never the less, 100BASE-T as it is described in IEEE 802.3-2018 is really more of a common super class (in programming terms) of the more concrete 100BASE-T2, 100BASE-T4, 100BASE-TX and 100BASE FX (100BASE-X being a common super class of 100BASE-TX and 100BASE FX).

Contrast this with 1000BASE-T (Gigabit Ethernet) which explicitly makes reference to twisted pair while Section 34 "Introduction to 1000 Mb/s baseband network" defines properties common to all 1000BASE physical layer and media types, effectively fulfilling the role of 100BASE-T in the 1Gb/s space. In this case, the "T" in "1000BASE-T" is clearly related to twisted pair.

Semanticscribe (talk) 13:51, 7 October 2021 (UTC)


 * Interesting find. However, I wouldn't put too much weight on that. 100BASE-T is used as an umbrella term for what is normally called Fast Ethernet. In common usage, 100BASE-T definitely refers a twisted-pair variant, most prominently (and ambiguously) to 100BASE-TX. In fact, 100BASE-TX and 100BASE-FX are very similar apart from the copper vs fiber fact (-TX just adds scrambling to remove DC bias) due to both being derived directly from FDDI. --Zac67 (talk) 17:42, 7 October 2021 (UTC)


 * Fast Ethernet says 100BASE-T is any of several Fast Ethernet standards for twisted pair cables... I have marked the statement as Dubious. If this is not supported by IEEE 802.3-2018, we need to rework it or find a reliable source that supports it. ~Kvng (talk) 14:34, 10 October 2021 (UTC)


 * I found three sources that support the assertion that 100BASE-T is a basically synonym for Fast Ethernet with 100BASE-FX under that umbrella:, , . I think some rework of the Dubious statement is needed. ~Kvng (talk) 15:48, 16 July 2022 (UTC)

8P8C wiring polarity might be wrong
I think the tables for "8P8C wiring (ANSI/TIA-568 T568B)" and "8P8C wiring (ANSI/TIA-568 T568A)" contain an error.

The differential pair 1 (blue) polarity is consistent with the other pairs in that table. - is blue and + is white/blue

I do not have an ethernet standard to confirm but the information i find online with consistency is the exact opposite. Only for the diff. pair 1.

Even though diff. pair 1 is not used for 100BASE-TX the notation in the table should be fixed imo Mtoaes (talk) 11:09, 6 December 2023 (UTC)


 * 100BASE-TX doesn't use pair 1, so it's not in that standard. Looking at 1000BASE-T (IEEE 802.3 Table 40-12), pair 1 is defined with 4+ and 5- – I think we should stick with that here. --Zac67 (talk) 12:16, 6 December 2023 (UTC)