Probably a silly question about wireless.

I am still pondering wireless ethernet solutions. This to be able to access the PLC from any location in the plants that we are making.

Being a complete noob in this respect, I have a possibly easily answered question:

What is the difference between a "Wireless Router" and a "Wireless Accesspoint" ?
For my purposes, to be able to connect wirelessly to my ethernet enabled PLC(s), which of the two do I need ?

are we talking about 2.4 ghz?

... imagine accesspoint (AP) as standart TP switch ... and router like repeater ... they always support DHCP or fixed IP and some WEP crypting (64/128bit) ...for you as user, it always act as "small pc inside network" and you can also see it's IP and configure it through some kind of web api ...

1] access point - is like server ... receiveing and sending data to clients
2] router - is just node B in wireless network sending signal from node A to node C (routers have physically two antennas - ap and client have one only - it may not have LAN connector)
3] client - can communicate only with access point .. simply one side is wirelles and on other is LAN RJ45 connector you put into your switch/pc/plc... anything

4] you will probably buy two same devices but configure one as AP and second as CLIENT

That didnt make me much cleverer ! (no offense meant marius).

"... imagine accesspoint (AP) as standart TP switch ... and router like repeater ... "
I have trouble imagining that because a regular router is like a clever version of a regular switch. A repeater is just a dumb device, so I cannot imagine a router as a repeater.

With "you will probably buy two same devices but configure one as AP and second as CLIENT" I guees you mean that I need a Wireless Accesspoint.
What does a Wireless Router do then ?

Most laptops these days have Wireless onboard.
What I am looking for is the hardware that will allow the laptop to connect to the PLC via ethernet/wireless.

Looking at the offerings from various vendors the terms "Wireless Router" and "Wireless Accespoint" are used. What is the difference between the two terms ? If any.
What does it mean to me in practical terms ?

Thanks Tark (you posted while I was replying to marius post).

I think that I get that an Access Point normally only has the hardware to connect an existing network into wireless.

The confusion that I get is that I have seen both "Wireless Accesspoints" and "Wireless Routers" that have "all in one" so to speak. For example Multiple LAN ports, Wireless antenna(s), ADSL port, ISDN port, RJ11 ports for telephones etc (for VoIP).

Is it just a case of two words for the same thing ?

Hello im new im an electrical apprentice and an assignment requires me to know and describe unitary, modular and rack mounted PLCs. Do you know and can direct me to a website or give me a brief overdraft. It would be much appreciated.

Jesper here is a glossary that defines terms http://www.symbol.com/products/wireless/glossary.html#terma

An Accesspoint is a bridge between wireless and an Ethernet wired LAN(s). Accesspoint devices are placed strategically to allow network access from different locations. In most cases the effective range is around 1800 feet. At my University I have wireless access to the Internet thru the schools wireless network, all thru the buildings you can see these little Accesspoint devices with antennas...like this one http://www.symbol.com/products/wireless/ap_300_ap.html

There are numerous architectures that can be used depending on what you want to do. If the plcs will be on their own WLAN and not connected to the corporate wired LAN then accesspoints may not be needed. Technically most wireless routers are AccessPoint devices and offer ports for connecting wired devices.

The simples method I know to understanding this is setup one of your plcs for wireless access, get an inexpensive router with wired access and "play" with it. This allows you to connect your already available wired PC thru the wireless router to the PLC.

Thanks, rsdoran.
So according to you an Access Point offers something that a Wireless Router does not. But I am still not sure what it is.
The glossary didnt say what a wireless router is.

Here are two products (just an example) that use the two terms:
3COM 3CRWE454G72 OfficeConnect Wireless 11g Access Point, 54Mbps
3COM 3CRWE554G72T OfficeConnect Wireless 11g Cable/DSL Router
Just to confuse matters the two cost exactly the same.

I feel uncomfortable not knowing which type to chose. I dont want to just buy something "blindly" and then hope it was the right decision.

For information, the PLC will be on regular wired ethernet. The idea is to be able to walk around with a laptop and connect from any location for HMI and even programming functions.

A wireless access point is nothing more than a wireless HUB. It's like connecting two wired hubs together to get you more ethernet ports. So it is going to be the easiest to set-up. The router is designed to route communications between two networks, for instance your home network and the internet. If you have an existing network and want to enable wireless on that network use a wireless access point, if you want to have two seperate networks you'll want to go with a router. Having multiple routers on the same network can be a pain to set up.

Aha !

I checked up on the specifications on the two models, and it appears that the "access point" model is just that. ONLY an access point.

The "Router" model provides the following:
"Combines a stateful packet inspection firewall, 4 port Fast Ethernet switch, ADSL modem and 802.11g wireless access point to provide secure, high-speed Internet sharing;.."

In other words, a wireless router includes an access point.

Then I am only puzzled as to why there is no price difference between the two .

well... it may be different for different models of different manufacturers ... this might be your case

http://www.alteruter.net/temp/plcs.net/topology_2.gif

... now i'm gonna get some sleep under the keyboard, because probably you are confused enough

hmm some kind of bug during cut&paste ...
http://www.alteruter.net/temp/plcs.net/topology_2.gif

JesperMP said:

Then I am only puzzled as to why there is no price difference between the two .

Click to expand...

Not sure, you can always ask them to charge you more if you get the router

I guess that's a good way to explain it, a wireless router is a router with a built-in wireless access point.

Marius - A wireless access point extends an existing network, a router connects two different networks together.

Thanks marius.
Go get some sleep please. That last diagram cleared up everything

As to the price difference, when I checked another vendor (OvisLink) then their cheapest Wireless Router was less expensive than their cheapest Access Point (!).

Can the explanation be that the dedicated Access Points have better wireless functionality or performance than the all-in-one router models ?