805911 - Radio signal strength is shown while no SIM inserted

Status: RESOLVED DUPLICATE of bug 817660

(Firefox OS Graveyard :: Gaia::System, defect)

Description

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

Radio signal strength in the status bar shows 4 out of 5 bars. But I have no SIM installed. Instead it should show a No-SIM or No-Signal icon there?

Comment 1

[Vincent Liu[:vliu]]

When I tried to reproduce this problem, there were something I have seen. The device I used is otoro.

1. Without SIM card, I got the voice.connected=false and voice.emergencyCallsOnly=true in /gaia/apps/system/js/statusbar.js. In this case, we can only dial emergency. When I also tried to observe icon.dataset.level in sb_updateSignal() , it got the level 5. I think it is also normal because even we don't have SIM card, we can still measure radio signal strength for dialing emergency call. 

2. In status bar, I saw there were Radio strength notification showed 5 bars without SIM card. I think there might be policy issue on showing Radio status in different case (With/Without SIM card). When I tried my android phone, there was a X showing on Radio strength notification. Maybe it needs a discussion with gaia.

3. I remembered the device will show Emergency(No SIM) on lock screen when no SIM is inserted. But In my latest build (today), I can only see Emergency Calls.

Comment 2

[Tim Guan-tin Chien [:timdream] (please needinfo)]

This is the expected behavior. The signal you are seeing is the signal strength for connecting Emergency calls. You should be able to see the "Emergency calls only (no SIM)" label on the lock screen.

Closing as invalid. Reopen if you disagree or if you think the behavior should change. We can pull in UX for the discussion.

Comment 3

[Vincent Liu[:vliu]]

(In reply to Tim Guan-tin Chien [:timdream] (MoCo-TPE) from comment #2)
> This is the expected behavior. The signal you are seeing is the signal
> strength for connecting Emergency calls. 

Yes, I agree with you that the signal strength for Connecting Emergency calls. But in unlock screen, users see the signal strength but doesn't anywhere tells user this signal notification is for emergency or for camped operator cell. I am afraid it easily confuses the user in unlock state. I think we should a better policy on showing it clearly.


> You should be able to see the
> "Emergency calls only (no SIM)" label on the lock screen.
> 

I synced this morning and I found "Emergency calls only" label on the lock screen. Observed conn.cardState in lockscreen.js, it showed the value is null. For this, I still look into it.

> Closing as invalid. Reopen if you disagree or if you think the behavior
> should change. We can pull in UX for the discussion.

In unlock screen, users see the signal strength but doesn't anywhere tells user this signal notification is for emergency or for camped operator cell. I am afraid it easily confuses the user in unlock state. I think we should have a better policy on showing it clearly

Comment 4

[Vincent Liu[:vliu]]

(In reply to vliu from comment #3)

> I synced this morning and I found "Emergency calls only" label on the lock
> screen. Observed conn.cardState in lockscreen.js, it showed the value is
> null. For this, I still look into it.
> 

I will file another bug for this.

Comment 5

[Stefan Arentz | :st3fan | ⏰ EST | he/him]

I assumed that it was not possible to make any call when no SIM card has been inserted. If that assumption is wrong then maybe this bug is invalid?

Comment 6

[David Scravaglieri [:scravag]]

Maybe signal strength for emergency call mark should be visible. UX input wanted

Comment 7

[Tim Guan-tin Chien [:timdream] (please needinfo)]

Josh, what does UX has to say regarding comment 3?

Comment 8

[Josh Carpenter [:jcarpenter]]

The current approach made sense in initial discussions a few months ago, but in practice I agree it's confusing. Tim, let's hide the indicator entirely when the SIM card is absent. This should alleviate the confusion, and is consistent with prior art. 

Beatriz, does that work for you?

Comment 9

[Beatriz Rodríguez [:brg]]

Thanks for asking.
I can understand your explanation about the lack of information in the status bar but when NO SIM is available user can make emergency calls( the strength signal comes from any of the network providers)

If you do not have any SIM card, and no coverage at all, then the signal strength should be 0, but this is regardless of the SIM card status ;-)

I will keep current implementation for strength signal because it is the right one: there is signal strength for making emergency calls when NO sim card is inserted.

If you want to improve this situation, IMHO there are two posibilities:
a) User can use the lock screen to get more information(current implementation)
b) Modify the status bar to add some icon or tag with more info for end user to know that only emergency calls are available but do not remove the signal strength.

Comment 10

[Josh Carpenter [:jcarpenter]]

(In reply to Beatriz Rodríguez [:brg] from comment #9)

Thanks for the response, Beatriz! Let me try to make a usability argument against showing the indicators:

> I will keep current implementation for strength signal because it is the 
> right one: there is signal strength for making emergency calls when NO 
> sim card is inserted.

This is a nice example of the difference between mental models and system models. The former represents a user's internal understanding of a system, whereas a system model is the engineering reality. Usability failures often occur when the designer focuses on expressing the "accuracy" of the system model instead of the user's shorthand model. An effective interface expresses the system as accurately possible, but does also anticipates and reflects the user's understanding (as well as general usability heuristics around complexity, affordances, etc). Accuracy does not equal 

In this case, it seems clear that users commonly associate signal strength indicators with the ability to make a phone call, and that the more accurate approach is therefore deceptive, and confusing, with consequences for user trust in the device.

We should also note how rare it will be for users to both lack a SIM card and be in an emergency situation where they need that information. Frankly, if I _was_ in an emergency scenario, I'd still try calling, regardless of what the signal strength indicator said.

That's my take, for v1.

Comment 11

[Josh Carpenter [:jcarpenter]]

(In reply to Beatriz Rodríguez [:brg] from comment #9)
> b) Modify the status bar to add some icon or tag with more info for end user
> to know that only emergency calls are available but do not remove the signal
> strength.

We could do this, but it's actually more work at this point (new icon design, and code to implement) than simply hiding the indicator, and also adds complexity to our Status Bar. I'd prefer the don't-show-signal strength approach.

Comment 12

[Beatriz Rodríguez [:brg]]

(In reply to Josh Carpenter [:jcarpenter] from comment #10)
> (In reply to Beatriz Rodríguez [:brg] from comment #9)
> In this case, it seems clear that users commonly associate signal strength
> indicators with the ability to make a phone call, and that the more accurate
> approach is therefore deceptive, and confusing, with consequences for user
> trust in the device.

If user try to dial, there is a warning message saying that the device is not registered. IMHO, we should improve this message so no user got deceptive when trying to make a call and forgot to insert the SIM card. We can indeed remind him to insert it.

> We should also note how rare it will be for users to both lack a SIM card
> and be in an emergency situation where they need that information. Frankly,
> if I _was_ in an emergency scenario, I'd still try calling, regardless of
> what the signal strength indicator said.
> 
> That's my take, for v1.

(In reply to Josh Carpenter [:jcarpenter] from comment #11)
> (In reply to Beatriz Rodríguez [:brg] from comment #9)
> > b) Modify the status bar to add some icon or tag with more info for end user
> > to know that only emergency calls are available but do not remove the signal
> > strength.
> 
> We could do this, but it's actually more work at this point (new icon
> design, and code to implement) than simply hiding the indicator, and also
> adds complexity to our Status Bar. I'd prefer the don't-show-signal strength
> approach.

IMHO, if we cannot include a new icon for this, I will keep current implementation(option a)

Comment 13

[Julien Wajsberg [:julienw]]

blocker of a bb+ => auto bb+

Comment 14

[Julien Wajsberg [:julienw]]

Marking dup feels better.