Since I won’t be at the TIA liaison ad hoc, below are inputs for issues you raised by TIA in their liaison, these are my individual comments, but written from a perspective of how the TIA group interacts with the 802.3cg process.
- Specification feedback on TIA single pair (reading the spec from the standpoint of IEEE 802.3 concerns)
- Section 4.1 aims to describe adaptation to four pair cabling. While cabling components may be useful for IEEE applications, we caution TIA that the published IEEE 802.3bw-2015, IEEE 802.3bp-2016,
and IEEE 802.3bu-2016 single pair standards are designed to substantially different insertion loss and DC resistance than existing TIA four-pair standards. Reading the text of the standard, it appears that the TIA standard is levying requirements on the
technologies which run over the cabling (“Applications running single pair cabling shall be supported by four pair cabling. “) Can you clarify this statement?
- Section 5.4.1 limits cord cable to a maximum of 24 AWG. Powering over single pairs under IEEE 802.3bu-2016 may support currents up to 1.36 Amperes, which may mandate heavier gauge cordage.
- Channel configurations: In addition to the 100m and 15m channel configurations in your draft, IEEE P802.3cg is working on specifying link segments up to 1000m using 18 AWG cable with up
to 10 inline connectors. In addition to process control industry applications, building automation systems have requested these long reaches. (see, e.g.,
- Cable heating due to power provision and bundling restrictions: it would be beneficial to specify allowed bundling configurations vs. temperature rise to manage cable heating from IEEE 802.3bu-2016
powering, similar to what was done for power over Ethernet in TSB-184-A. Such an effort would ideally track any extensions made to single-pair powering which are within scope of 802.3bu.
- Progress on Multidrop
- The IEEE P802.3cg group in considering a multidrop toplogy of up to 25 meters in length with up to 8 nodes. While designed primarily for automotive applications, it is our experience that
such technologies find use beyond their original application. Further details of the link segment and topology, including representative performance, may be found at
- The IEEE P802.3cg group has not yet engaged in a detailed discussion of connector characteristics. Our work to date has been focused on selecting baselines for the PHYs and powering.
We will keep you informed when we do so.
We should also send them the next draft of IEEE P802.3cg.
Additionally, we should convey the draft to ISO as well.
George A. Zimmerman, Ph.D.
President & Principal Consultant,
CME Consulting, Inc.
Experts in PHYsical Layer Communications
From: Valerie Maguire [mailto:Valerie_Maguire@xxxxxxxxxx]
Sent: Monday, November 06, 2017 1:51 PM
To: Christopher T. Diminico <cdimi80749@xxxxxxx>; Shariff, Masood (mshariff@xxxxxxxxxxxxx) <mshariff@xxxxxxxxxxxxx>; Sterling Vaden <sterlingv@xxxxxxxxxxx>
Cc: George Zimmerman <george@xxxxxxxxxxxxxxxxxxxx>
Subject: Tomorrow Grand Sierra B, 1:30pm - 3:30pm
Folks – Please plan on participating in the effort to draft a response to the TIA incoming liaison tomorrow at 1:30pm in Grand Sierra B.
Thanks - Val
Valerie Maguire, BSEE