Connection terminated by remote user, why?

[PingISTL]

Dear All

I tried to connect to an apple device, it is successful but soon after that, it is disconnected with reason code 0x13 - terminated by remote user, I tried to change the connection parameters to its preference, and disconnection still happens . Here is the log file using nrf connection desktop as suggested by the post here connection parameters ,  sorry I accidently closed the ticket, so have to open a new discussion here. The MAC address of the device is AC233F8153CE, the connection/disconnection happens at the end of logs. Can someone have a look at it and let me know the reason please?

Thank you.

Ping 

2022-06-14T11_22_34.031Z-log.txt

[Sigurd]

Hi,

A sniffer trace might give us some more insight to what happens. Please capture a sniffer trace of the behavior. https://www.nordicsemi.com/Products/Development-tools/nRF-Sniffer-for-Bluetooth-LE

[PingISTL]

Hi, Sigurd

I don't think my application is calling the disconnect function somewhere, here is the screenshot for it. the highlighted line on No 329, seems like the slave is initiate the LL_TERMINTE_IND, am I right? 

Also, it happens with nrf Connect mobile app when I try to connect it with my phone. But this doesn't happen with BeaconSimulator App running on phone.

Regards!

Ping

[PingISTL]

Unfortunately, this is one of Apple's product, and I don't have source code to access it, my project now is develop an central application talking to other peripherals like this one.

Thank for reply!

Ping

[Sigurd]

Ok, I see. Maybe you could try the Apple Developer Support. https://developer.apple.com/support/

[PingISTL]

Hi, thanks

I will try to read the apple development support.

nrf connect app seems to be same, but another app - BeaconSimulator is able to talk to it without being disconnected.

I tried change connection parameters, and doesn't help, any thing you could think? 

Ping

[Sigurd]

PingISTL said:

BeaconSimulator is able to talk to it without being disconnected.

Hmm, do you have sniffer trace with that? So we can compare it with the other sniffer trace?

[PingISTL]

I will try to catch it and send, thanks!

Ping

[PingISTL]

CEConnectWithPhone.pcapng

Hi, Sigurd

See the attachment please. It was caught a few days ago, I tried to do it again today and unfortunately, the sniffer doesn't work for me now. It sees advertisng packets, but doean't seems catch the connection activities. Not sure why.

Thank you!

Ping  

[Sigurd]

PingISTL said:

See the attachment please. It was caught a few days ago,

Here we can see the central do a service discovery, does read requests, enables notifications, etc. So the activity here likely makes the connection stay alive. If there is no activity, you just connect, the slave in the other sniffer trace seems to detect that, and deliberately disconnects after a timeout period with no activity. 

[PingISTL]

possibly, but some other peripherals do not do that - just stay connected even no activities going on. 

I am about to do service discovery immediately after connection, have a question here - how do I determine which service UUID I pass to the discovery manager? for this particular one, it seems advertising manufacturer data which has its own manufacturer ID and 128 bits service UUID, so I presume I need to know the manufacturer's advertising data protocol ? is this published somewhere?

Thank you for your patience!

Ping

[Sigurd]

Probably easiest is to use e.g. nRF Connect Desktop BLE app, or nRF Connect for mobile app, connect to the device, and check out the services and UUIDs.

[PingISTL]

I am developing a central app - a generic one applies to all peripherals hopefully, so need to figure out what other centrals do in terms of findings all services and UUIDs - there must be a procedure/way for these centrals like nRF Connect to follow to find all services available from any peripheral without knowing its protocols already - am I right?   

Regards!

Ping