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Re: [802.3_10SPE] Single Twisted Pair Ethernet over AWG 22-24 type cable ?


My response is that the ISO standard for generic enterprise premises cabling for supporting ALL IT applications has now been an approved standard for over 20 years (ISO/IEC 11801-1995).  Conformant cabling to support it has been available in the broad marketplace at commodity prices for all of that time.  

Class D/Category 5 cables are not just "Ethernet cables" (per you below).  The intent was ALWAYS that 11801 category cabling be recommended for IT/data use in general.  Although 2-pair Cat 5 was allowed for installations, 4-pair has always been recommended.  When installing cabling in a facility, the installed cost difference to place 4-pair cabling is trivial and far less than the capital investment cost by the silicon industry to develop a new PHY.

What part of this equation is it that your industry does not understand and you want us to fix "without changing anything"?

BTW, the above argument has nothing to do with the market opportunity equation presented to 802.3 by the automotive industry.


Geoff Thompson

On Dec 20, 2016, at 8:01 AMPST, patrick Mourot <patrick.mourot@xxxxxxxxxxxxxxxxx> wrote:

Dear 802.3cg,

In industrial building Profibus type cable is deployed but some other types of cable are present in those structures.

Today, in most of them we also find single twisted pair cables (screened or unscreened) cabling for telecommunication purposes particularly for TDM (Time Division Multiplexing) telephonic systems.The typical application is to transport Voice and Signalling messages between devices.

This cabling system is provided at a low cost and lot of cabling installers are well aware of its specifications.

Having Ethernet over the existing wiring system in the buildings will provide a solution to migrate traditional TDM equipments towards the IP world. While keeping the current cabling the solution becomes cost effective : it requires only changing devices (i.e. VoIP phone sets instead of TDM ones). The solution needs only minor investments (put in place some Ethernet switches) but no civil engineering is required to deploy specific Ethernet cables (e.g. Category 5 or Category 6). De facto, this optimizes the overall cost of the IP infrastructure.

The single twisted pair cable is similar to AWG 22, corresponding roughly to Æ 0,6 mm copper or AWG 24 corresponding roughly to Æ 0,5 mm copper.

The cable characteristics are :

-80-135 Ohms at 700 kHz with a 25dB max attenuation between 340 and 680 kHz.

-types : SYT0.5 & SYT0.6 or 278 or ITT 26626 BBEB DEBE or TsR-R depending on the country with a range between 800m and 1200m.

The decreasing loss with a constant of 15dB per decade of frequency and a 44dB loss at 700 kHz (90% level of confidence).

An artificial line equivalent to 900m of LY0.5 cable (Æ 0,5 mm copper) could be as follow:

We are wondering if the802.3cg group could have some interests for consideration in standardization of Ethernet (10Mb/s ?) on this type of cable.

Feel free to comment and thank you for your feedback.


P. Mourot