Backlight lights up based on SIP session expire

[CFortC]

I have this problem with both a T48G and a T48S each running respective most recent firmware. I've re-tried on every earlier firmware version still downloadable, with no resolution. I've factory reset and reconfigured, etc. with no resolution.

The issue is that the dimmed (or power-saved off) backlight will return to ON status whenever the SIP server registration expires (account.X.sip_server.1.expires) . For example, if that is set to 300s, then the backlight returns to ON every five minutes. This is quite annoying over time.

MAJOR additional information: with just one SIP account registered, this problem does NOT occur. However, my normal setup has two distinct SIP accounts. The enabling of the second account also activates this problem.

In researching the issue, I noticed that a similar problem was reported in the "T2xP Series" forum as thread "T22P display backlight lights up every 2 mins". That was around 2014 and that issue was eventually fixed with a firmware update. For the T22P issue, the number of SIP accounts registered wasn't specified. Perhaps the T22P user had only one account registered. I only mention this T22P problem because of the similar symptoms to what I'm seeing today with my T48G and T48S.

Any others seeing this issue? Any different configuration I need to set to allow two SIP accounts to run the backlight properly? Firmware Fix possible? (T48G is end-of-life, so access to an OLD firmware without this problem would also be acceptable.)

Thanks in advance for any help.

[complex1]

(09-09-2020 01:56 AM)CFortC Wrote:  I have this problem with both a T48G and a T48S each running respective most recent firmware. I've re-tried on every earlier firmware version still downloadable, with no resolution. I've factory reset and reconfigured, etc. with no resolution.

The issue is that the dimmed (or power-saved off) backlight will return to ON status whenever the SIP server registration expires (account.X.sip_server.1.expires) . For example, if that is set to 300s, then the backlight returns to ON every five minutes. This is quite annoying over time.

MAJOR additional information: with just one SIP account registered, this problem does NOT occur. However, my normal setup has two distinct SIP accounts. The enabling of the second account also activates this problem.

In researching the issue, I noticed that a similar problem was reported in the "T2xP Series" forum as thread "T22P display backlight lights up every 2 mins". That was around 2014 and that issue was eventually fixed with a firmware update. For the T22P issue, the number of SIP accounts registered wasn't specified. Perhaps the T22P user had only one account registered. I only mention this T22P problem because of the similar symptoms to what I'm seeing today with my T48G and T48S.

Any others seeing this issue? Any different configuration I need to set to allow two SIP accounts to run the backlight properly? Firmware Fix possible? (T48G is end-of-life, so access to an OLD firmware without this problem would also be acceptable.)

Thanks in advance for any help.

Hi,

What happens if you play with larger time settings, stay the backlight dimmed?
Try default setting of 3600s, 600s, 900s, ...

[CFortC]

[/quote]

Hi,

What happens if you play with larger time settings, stay the backlight dimmed?
Try default setting of 3600s, 600s, 900s, ...
[/quote]

I've working with pretty much all the timeout settings at 3600s (the default for most of them) and these have no effect.

The only setting that DOES effect the "Backlight On" interval is Server Expires. With this set to 300s (my VoIP provider's recommendation), it normally lights up every 5 minutes. With this set to 600s, the characteristic time is 10 minutes. And so on. The testing is pretty conclusive, as far as I can see.

[Yisroel_MongoTEL]

(09-09-2020 01:56 AM)CFortC Wrote:  MAJOR additional information: with just one SIP account registered, this problem does NOT occur. However, my normal setup has two distinct SIP accounts. The enabling of the second account also activates this problem

Given that account 1 doesn't cause this issue, have you tried comparing all the SIP settings between the 2 accounts? Maybe some difference there?

[CFortC]

Very good question. To confirm the settings are identical (except for user name, password) I exported the phone settings to CFG (text) file and arrayed the two account settings side by side in Excel. Identical.

I then re-checked the settings on the VoIP provider configuration site. If there are any differences, they elude me for now.

To get to the point, I tested with the first account registration disabled, and only the second one enabled. So just one account active: voila! the backlight now comes on every interval. However, the interval is not the Server Expires time (say 300s) but exactly one-half the Server Expires time (150s in my case). What the?

For sanity's sake, I re-tested with both accounts active: the backlight comes on every one-half of the Server Expires time. This is different from what I thought I was observing yesterday, but it is definitely the case today.

Finally, I re-tested with only the first account active: the backlight stays OFF, just as before.

Given all the scouring of the phone settings that I've done, this is quite mysterious. Since it's happening on two phones (the T48G and T48S), it does in fact point to something on the VoIP provider side, tied to the second account. I will continue scouring those settings and report any results.

[Yisroel_MongoTEL]

(09-10-2020 02:07 AM)CFortC Wrote:  Given all the scouring of the phone settings that I've done, this is quite mysterious. Since it's happening on two phones (the T48G and T48S), it does in fact point to something on the VoIP provider side, tied to the second account. I will continue scouring those settings and report any results.

Account 1 and 2 are different VoIP systems?

Maybe try putting account's 2 creds in account 1 as the only account and see if the lights come on...

[CFortC]

Yesterday I reviewed every setting on both the T48G and the T48S, and also reviewed every setting on the VoIP provider's web site for account settings, for both accounts. I found a few settings that might not be 100% copacetic and adjusted those. Examples include: DHCP priority for time setting (I prefer NTS), G.911u CODEC offered by provider (not supported by Yealink phones), etc. - pretty minor stuff, hopefully not impacting the issue, but I cleaned them all up anyway.

In the course of the day, I also discovered the actual issue, which following my clean-up, now appears only on the T48G. It turned out to be an uncontrolled external factor: the presence of unread voicemail in the VoIP account.

In summary, with unread voicemail pending in the account, the T48G backlight turns on regularly. This applies to both of the VoIP accounts (the reason I hadn't observed it from the first account was that it was set up to delete the voicemail when sending an email notification of the voicemail). The workaround is to set Account => Advanced => Voice Mail Display to Disabled (account.X.display_mwi.enable = 0). I give up the flashing LED when there is a waiting voicemail but with my email notifications I can live with that.

Although I thought I observed the same issue on the T48S, the backlight ON issue is no longer present there. It's OK to leave Voice Mail Display enabled, and the flashing LED works fine. Perhaps the settings cleanup fixed it, or some other factor intervened of which I'm still unaware, but the issue is gone now. Or perhaps the issue was never there, though that is not what I recall seeing.

The T48G is running T48-35.83.0.120, the latest firmware available and likely the last version to be released for this end-of-life model.

The T48S is running T46S(T48S,T42S,T41S)-66.84.0.90.rom, not the very latest but I'll probably go ahead and bring it up-to-date now that I think I understand the issue.

Thanks to all who replied with suggestions and questions!