Talk:Physical layer/Archive 1

rewriting of article

Listen, I'm considering rewriting this article in the following way:

• removing the discussion of 2B1Q (perhaps mentioning it as an example) and the "sublayer"
• addressing the fact that the medium can be electrical, RF, or optical
• addressing the complexities of physical layer signalling by linking to articles on: (assuming these exist)
  • digital signal processing
  • modems
  • modulation
• adding a short discussion of physical layer interfaces in a typical PC

In general, I feel that the existing article somewhat confuses the role of the interface and overly simplifies physical layer processing as mere electrical pulses on a wire. This may be true for old standards, but certainly does not hold for any physical layer standard developed since the mid-1980's.

Any comments? RobertYu 21:41, 15 Sep 2004 (UTC)

Good points. I have tried to address them. Mange01 00:16, 9 November 2006 (UTC)

physical mail system

Would not a better analogy for the physical mail system be the vehicles that transport the mail, rather than "a specification for various kinds of paper and ink"? BevanFindlay 22:16, 18 July 2006 (UTC)

Agree. Or perhaps the entrance to roads that transport the vehicles that transport mail? Mange01 00:16, 9 November 2006 (UTC)

Agree, changed to roads. Conrad.Irwin 15:48, 14 December 2006 (UTC)

names for the various parts

Is there a standard pinout for putting EIA-485 on a RJ-11 6P4C or RJ-45 8P8C connector? (Does 10BASE-T specify this, or are the signals on a 10BASE-T cable *not* EIA-485 signals?)

I would like to fill in the holes in this table:

• "RS232D", aka "EIA/TIA-561", is the standard for "RS-232 on a RJ-45 8P8C connector"
• EIA-530 is (?) the standard for "RS485 on a DB-25 connector"
• ???? is the standard for "EIA-485 on a DE-9 connector"
• ???? is the standard for "EIA-485 on a RJ-45 8P8C connector"
• RJ50 is the standard for "???? on a ???? connector"
• 10BASE-T is the standard using ???? on a RJ-45 8P8C connector.

This table distinguishes "the electrical voltages" from "the mechanical plug shape and how the wires are twisted" from "some standard that defines which voltage goes on which physical conductor". Is there a name for these 3 things? Yes, OSI model calls all 3 things taken together the "Physical Layer", but is there 3 different names for these 3 part?

--65.70.89.241 17:35, 2 August 2006 (UTC)

First, you'll want to correct the naming of "RJ-11" and "RJ-45" connectors. You mean modular connectors. RJ11 and RJ45 are telephone wiring standards. (Also, they don't have hyphens). I have recently updated some of the wikipedia articles on these to make that more clear. The RJ50 article is apparently incorrect in this same way, but I haven't had a chance to look up what an RJ50 registered jack really is.

Bryan Henderson 17:50, 9 September 2006 (UTC)

I've seen some pinouts that could be used for EIA-485 on a 6P4C or 4P4C connector[1], giving 1 pair for data and 1 pair for power, apparently defined by the CANopen standard.

Alas, when I try to fill in the small gaps in my knowledge, I start to realize that what I don't know is vastly larger than I thought it was.

Thank you for pointing out those things are called modular connectors.

Fixed the connector styles ... anyone know how to fill in the remaining gaps? --68.0.124.33 (talk) 05:31, 17 July 2008 (UTC)

Vote: Four and/or five layers in the TCP/IP model template and wiki articles?

Give your vote here. Should the TCP/IP model template have four or five layers? I.e. should the physical layer be a separate layer or not? And what should the the bottom layer be named in case of four layers? And is it okay to mention both the four and five layer TCP/IP models in Wikipedia articles? Mange01 (talk) 18:24, 17 July 2008 (UTC)

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was no consensus for move. Aervanath lives in the Orphanage 04:26, 8 January 2009 (UTC)

---

I believe this move should be undone (the move was made along with several other {{OSIModel}}-related moves). WP:MOSCAPS issues can be tricky, but in my mind the issue boils down to whether this article is OSI-specific.

This article covers both OSI and non-OSI issues — point-to-point and bus topologies aren't OSI, but still have PHYs. While it might be possible to split the article into two parts (a general-purpose physical layer, and an OSI-specific Physical Layer (OSI) or somesuch), it seems far more sensible to leave this as a single article that covers both OSI and non-OSI issues, and name it 'physical layer' to reflect its general-purpose nature. --Underpants 15:20, 2 January 2009 (UTC)

The main focus of this article has long been the layer of the networking model of OSI. 'Layers' don't exist by themselves, a layer is only a layer as an entity within some framework. I doubt that the term 'Physical Layer' ever causes anyone to not associate it with the OSI model. I would say that in other uses the term 'hardware level' is more common. If there are examples in this article that for some reason do not qualify as OSI-relevant technologies, they should probably be moved to the PHY or other fitting article. Kbrose (talk) 16:37, 2 January 2009 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

The media itself

It is not clear that for instance a cable itself is considered physical layer or that only the signals are physical layer. When doing a bottom-up aproach based on the OSI model the first step is to check the wiring. (According tot Cisco CCNA 4.0 module 1) So, is a cable itself considered physical layer or not? —Preceding unsigned comment added by 85.145.222.194 (talk) 22:23, 26 May 2010 (UTC)