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What Are These Arrows (and why are they still here)?

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If you've used a Windows Mobile phone device, you've probably seen the little signal strength icon at the top.  If you're lucky, you live in a place with good signal strength and see many bars.  If you're like me, you live in a cellular dead spot and are happy when you get one bar. 

On many non-WM phones, the part of the icon that's not bars looks something like an antenna--a vertical line with a triangle on top of it.  While you sometimes see this antenna icon on WM Phones, it's often something else.  And, what that "something else" is varies from device to device.  On some it's a G.  On others it's an E.  On still others it's two arrows pointing left and right.  What are these things?  What did they do with our beloved antenna triangle?  And why won't they go away?

It's all about the data

If your signal strength icon has something instead of an antenna, it means that your device has a network address (an IP address).  This means that it can send data to and receive data from the internet.  The arrows are our default "data connected" icon.  They're often used by CDMA networks for both 1xRTT connections and EvDO connections.  OEMs and Mobile Operators have the ability to customize that icon, and often replace the arrows with other things.  GSM devices usually have a small "G" or an "E." (Don't confuse these with the larger G or E icon to the left of the signal strength icon.  I'll talk more about those later.)  The G usually means that you have a GPRS connection and the E usually means you have an EDGE connection.  However, some devices can connect to and get faster EDGE speeds but only show the G icon.

Why doesn't it go away?

In our 2002 release, when an application requested a connection to the internet, we'd create a connection.  Then, when the application said it was finished with that connection, we'd tear it down.  In our 2003 release, we changed this behavior to the current one.  Once you've connected once, it stays connected.  We made this change for a number of reasons, not the least of which was that it allowed a much better user experience.  In 2002, whenever you wanted any data from the Internet, you had to wait a few seconds for the device to request an IP address from the network.  Staying connected all the time means that you get data much more quickly.  Also, Mobile Operators requested it.  It was more expensive for them to be constantly creating and tearing down connections than to just do it once.  Finally, staying connected enabled us to develop a fast "push email" client that relied on the device holding an IP address.

It's important to understand that we only do this on connections with "Suspend/Resume" functionality.  These kinds of connections are suspended when a phone call comes in and resumed again when it is finished. 

Doesn't this cost me money?

In general, no.  A long time ago phones sent data over "circuit switched" connections.  These were similar to old style modems on your PC.  They would make a phone call and send data over that voice connection.  The Mobile Operator couldn't really tell the difference between those calls and other voice calls, so they charged per minute.  Current data connections (GPRS, etc), though, are different.  For these types of connections, every Mobile Operator that I'm aware of now charges per byte transferred, not per minute.  So you can keep your data connection on all the time and only get charged when you send or receive over it.

What about my battery life?

Just having a data connection shouldn't affect your battery life.  Most of the time, the device isn't doing anything with that connection.  It just sits there idle.  If you're sending a lot of data over the connection, though, that will definitely impact your battery life.  Unfortunately, the arrows don't really tell you whether you're sending data or not (though I've seen devices that animate the arrows while data is being transferred).

There's another box, what does that mean?

Sometimes you see a larger box to the left of the signal strength icon.  This one usually says G, E, 1X, or Ev for GPRS, EDGE, 1xRTT, or EvDO.  This icon says that the device can see that sort of network, but doesn't necessarily mean that it's connected.  It's more of a, "This network is available," notification than anything else.  The icon is often replaced with other notification icons, so you don't always see it.  Its biggest benefit, in my opinion, is that it will tell you on a CDMA device whether you're currently getting 1xRTT speeds or the much faster EvDO speeds.

Other questions?

That's pretty much what I know on the subject.  But if you have other questions, ask away.  I'll see if I can find answers for you.

Mike Calligaro

Comments

  • Anonymous
    July 14, 2006
    PingBack from http://microsoft.wagalulu.com/2006/07/14/what-are-these-arrows-and-why-are-they-still-here/

  • Anonymous
    July 14, 2006
    Doesn't phone send keepalive bits? What about if there is an established TCP connection?

  • Anonymous
    July 14, 2006
    Mike, here is one simple question. If we have a data connection open to a server and we are waiting for a response say for up to 15 minutes, but don't want to be wasting battery power on this - what is the best way to do this at the socket level?

    We've tried two ways:
    Poll the socket every 2 seconds. Bad.
    Have the socket command timeout after 15 minutes. This doesn't seem to work reliably.

  • Anonymous
    July 15, 2006
    I have a T-Mobile MDA and it doesn't seem to always a connection open. In particular, it seems that whenever ActiveSync connects to my Exchange server to synchronize, it then closes the connection after the sync. Is that something that T-Mobile did? I don't see a setting in ActiveSync to tell it to disconnect or maintain a connection after a sync.

  • Anonymous
    July 15, 2006
    How do 1xRTT and EvDO connections relate to UMTS or is there a special sign for UMTS?

  • Anonymous
    July 16, 2006
    Have you ever looked at your Windows Mobile device and wondered what all of those little indicators mean? ...

  • Anonymous
    July 16, 2006
    PingBack from http://justanothermobilemonday.com/Wordpress/2006/07/16/windows-mobile-understanding-signal-strength-other-icons/

  • Anonymous
    July 16, 2006
    This was useful, and nice and concise.

    Have mentioned it / linked to it at:

    http://justanothermobilemonday.com/Wordpress/2006/07/16/windows-mobile-understanding-signal-strength-other-icons/

  • Anonymous
    July 17, 2006
    As usual great and worthwhile explanation.

  • Anonymous
    July 17, 2006
    Is there a way of changing the "This Network is available" icons?

  • Anonymous
    July 17, 2006
    How do I prioritize the different types of networks my device can connect to when an application requests a connection?

    I.E.  
    1) WiFi
    2) EDGE || GPRS

    I am using a 3rd party WiFi network driver, is  it possible that it is not notifying the device of it's connection status and that is why a cellular data connection is attempted?

    How would a driver notify the OS that it is connected?

    Cheers,
    Chris

  • Anonymous
    July 17, 2006
    Maybe I have misread (twice) your explanation. I have 2 WM5 devices, a JasJar and K-Jam. Both do the same thing, which is show the antenna above the bars. Then, the big "G" (disconnected but available data connection) turns to a little G with the arrows, which animate when AS is syncing with the server, but in no other circumstance.

    What devices dispensed with the triangle on a pole icon, because these AKU2 Imate's didn't.

  • Anonymous
    July 17, 2006
    Josh, Akac, and Ness, I'm investigating your questions.

    Frank, it's certainly possible for TMo to configure its network and devices to not do always connected.  However, I've never seen them do that.  They were one of the original proponents of having us go to the "always connected" model.  On your MDA, when it first connects to a GPRS/EDGE connection, you should get a little bubble that pops down from the signal strength icon and stays up for a few seconds.  Are you seeing that repeatedly?

    MikeH, 1xRTT and EvDO are CDMA technologies (used by Verizon, Sprint, and Korean MOs).  UMTS is the followon to GPRS/EDGE and is a GSM technology (used by TMobile, Cingular/AT&T, and pretty much everywhere else in the world).  It's unlikely you'd ever see EvDO and UMTS icons on the same phone.  I don't live in a place with UMTS, so I've never seen the UMTS icon.  But, if the G for GPRS and the E for EDGE are any indication, I'd guess it will be a U.

    Ricardo, the OEM has the ability to change the icons.  I'm not aware of any way for end users to do so.

    Patrick and Steve, I'm glad you found the post useful.  

    Mike

  • Anonymous
    July 17, 2006
    The comment has been removed

  • Anonymous
    July 18, 2006
    Great information!  I own a Q and it shows the little arrows for most of the day but in the evening or after no use for some time I finally get the Antenna Icon.  I am not sure why it would revert back to the antenna,  Did it lose the connection?
    Thanks in Advance

  • Anonymous
    July 20, 2006
    so what happens if you have to use a GSM connection? It means you can't disconnect? I'm using a hp hw6915 and if you hold down the red end call key to disconnect the GSM connection it disconnects then starts to redial it. We use the GSM connection in places where GPRS is not supported. If we can't disconnect it will run up huge international phone bills. Any way around this? It seems like no one thought about anything other than using GPRS. Is there any way to add the old disconnect option to the pop up bubble?

  • Anonymous
    July 21, 2006
    The comment has been removed

  • Anonymous
    July 23, 2006
    "However, some devices can connect to and get faster EDGE speeds but only show the G icon."

    My HTC TyTN seems to be one of these devices. I seem to be getting EDGE speeds, but the icon is only showing G. Why does this happen? Is there anything I can do to turn on the E (and U & H) icons?

  • Anonymous
    July 24, 2006
    This is speculation on my part, but it's possible that the E, U, and H icons aren't on the phone.  Those icons all come from the OEM.  If they build an image for a mobile operator that doesn't support the other technologies, they might leave the icons out.  

    Mike

  • Anonymous
    July 24, 2006
    The comment has been removed

  • Anonymous
    July 24, 2006
    The solid triangle to the left of the signal strength one is the "roaming" icon.

    Mike

  • Anonymous
    July 24, 2006
    Is it possible for a 3rd party app to control those icons in any way?

    marc

  • Anonymous
    July 25, 2006
    Marc, can you describe more what you want to do?  It would be bad if an ISV app could say, "Even though we're roaming, I'm going to hide the roaming icon so the user doesn't know it," etc.  

    Mike

  • Anonymous
    July 26, 2006
    The comment has been removed

  • Anonymous
    January 23, 2007
    I am using a Windows Mobile 2003 device in Thailand where GPRS is charged by the minute. I am getting a huge bill due to the the inablity to hang up. I understand it was rectified in WM5. Is there a fix available for 2003? Thanks

  • Anonymous
    August 02, 2007
    Hi, I found this page to explain status icons. http://www.microsoft.com/windowsmobile/help/smartphone/icons.mspx I'm curious about one I don't see listed.  In the bubble that appears when I tap on the signal icon, I see a phone receiver next to an open lock.  Any idea what that means?

  • jevans

  • Anonymous
    August 16, 2007
    The comment has been removed

  • Anonymous
    August 16, 2007
    The only way to get these services run over WiFi is to disable the phone connection. And on the other hand this clearly shows that none of the data transfer service NEED GPRS, they only need a network route. So why is WiFi not marked as the cheapest route?

  • Anonymous
    August 18, 2007
    The comment has been removed

  • Anonymous
    August 25, 2007
    " Just having a data connection shouldn't affect your battery life.  Most of the time, the device isn't doing anything with that connection.  It just sits there idle. " Is that true on all networks?  I just switched from GSM to CDMA, and my battery life is much worse with the Sprint Mogul (HTC 6800). Finally narrowed it down to the connection being left open.  Also see: http://www.howardforums.com/showthread.php?t=1210770 Is this a "bug" in the phone that could be fixed, or a design issue with CDMA?

  • Anonymous
    August 26, 2007
    In GSM, when you are constantly attached to GPRS, your battery does not spend more energy because there is absolutely no communication between the network and device if there is no data transfer (however there is still periodical normal GSM communication). Only difference is if you are in motion and changing cells in time. Network keeps track of your GPRS connection via "routing area" which consists of one or group of cells. When you switch to cell that belongs to adjacent routing area, there is a, very short, "routing area update" exchange of information between phone and network, regarding GPRS only. But that is very small power consumption. The same thing is with UMTS. The whole goal of any network is to bring communication traffic to minimum. But, with UMTS, channel coding and transmitting technique is much more complex than with GSM. You are attached to multiple cells at the same time and there is very, very, very strict phone transmit power control. That means that phone must do a lot more signal measurements from group of cells (much more frequent than GSM). It could possibly happen, if you reserved more channels for packet data transfer, that a lot of signalling happens. However, there is a inactivity timeout here which puts you in standby mode as in GSM and then you do not spend battery for packet data at all. But this is all complicated, it depend of many factors: signal strength, network settings, number of users in your location area, etc. .. If the network signal is weak, than any phone in any type of network will eat up your battery.

  • Anonymous
    July 13, 2008
    I have a problem with my ETEN X500+ WM6. Sometimes, GSM signal icon keeps showing that it is searching for a network (...) or even that there is no signal available (!), but the phone is working, and I can even see the signal level (around 20%) using an external plugin. Anyway to fix this? It would be nice if the icon reflects the real state of the signal.

  • Anonymous
    December 29, 2008
    ok I have the E above the signal bars, the big E to it left and a triangle pointing up on the left of the big E. What is this triangle? it just came from nowere. and it also appear on the operators ballon at the right of t-mobile, above connected.

  • Anonymous
    January 19, 2009
    My personal opinion is that the connection should idle at least over night, or during off-peak times when there is no reconnection so often and the radiations caused by the gprs/3G/EDGE connection could be avoided. What do you think?

  • Anonymous
    May 29, 2009
    Hey Mike, Thanks for your explanations. Once and a while I get an sattelite dish icon to the left of the G icon on my HTC P3600. Do you (or anyone else) know what this icon means? I also get a Notification in the bottom left of my screen but selecting it shows no message. The only way to get rid of the icon and the blank Notification is to do a soft reset. I have searched on the net but have found no reference to this satellite dish icon. Thank you.

  • Anonymous
    May 29, 2009
    I meant I get "a satellite icon" to the left of the G icon. :o)

  • Anonymous
    June 30, 2009
    Short question: My Xperia X1 shows a the large available connection types, e. g. G or E, sometimes after a while with thin diagonal crosshatches... what does that mean? Data connectons are not active in this cases.

  • Anonymous
    July 07, 2009
    Mike, what about the Windows mobile icon that looks like three or four z's?  Common sense would dictate the device is not communicating with the network (sleep mode, in a sense), but what prompts that z-icon to appear?

  • Anonymous
    July 08, 2009
    The comment has been removed