Anyone have the issue where SPP device doesn't show up?

[Michael Wolthuis]

Anyone have an issue where the cu.device and tty.device shows up, but not the SPP serial port?

 

I feel like this occurred before, but I can’t figure out the actual resolution.

 

This is on Monterey, but seems the issue occurred before in the previous OS too.

 

Mike

W8MW

 

[Weston Bustraan]

Actually, a Bluetooth device that supports SPP will create just the cu and tty devices. As a general rule, the /dev/tty.* devices are for incoming connections and the /dev/cu.* are for outgoing connections, like a modem. The Mac IO service provides two keys, "IOCalloutDevice" and "IODialinDevice". 

For the Mobilinkd TNC3, which supports the Bluetooth SPP profile, this looks like:

IODialinDevice: /dev/tty.TNC3Mobilinkd-Mobilinkd

IOCalloutDevice: /dev/cu.TNC3Mobilinkd-Mobilinkd

Right now, QTH uses the latter, because TNCs are basically modems. 

I think in your case, though, you have the /dev/cu.* device, but no data can be read from it. This is very odd. Normally both devices work the same for terminal-type communications.

- Wes W8WJB

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[Michael Wolthuis]

Should I be able to cat the cu device like the tty device?

Sent from my iPhone

On Jan 7, 2022, at 6:57 PM, Weston Bustraan <wbus...@gmail.com> wrote:



[Weston Bustraan]

I am able to on my X1C5, but keep in mind that if there are no incoming packets, you won’t see any KISS data. I have mine configured to send GPS data over Bluetooth as well, so at least I see the NMEA sentences every second. That’s a good indicator that the serial connection is working

- Wes W8WJB 

[Michael Wolthuis]

To further complicate the strangeness….  The device is showing disconnected in Bluetooth preferences when the data is flowing with cat on with tty or cu.  If the device shows connected to Bluetooth, no data flowing.  

 

What the world…. Now I am really confused.

 

Mike

[Michael Wolthuis]

Well I’ll be an uncle…. Shows disconnected in bluetooth, now working fine on QTH….

 

Makes no sense..

 

Mike

 

 

From: Weston Bustraan <wbus...@gmail.com>
Date: Friday, January 7, 2022 at 9:00 PM
To: Michael Wolthuis <wolt...@gmail.com>
Cc: qthapp-users <qthapp...@googlegroups.com>
Subject: Re: Anyone have the issue where SPP device doesn't show up?

 

I am able to on my X1C5, but keep in mind that if there are no incoming packets, you won’t see any KISS data. I have mine configured to send GPS data over Bluetooth as well, so at least I see the NMEA sentences every second. That’s a good indicator that the serial connection is working

[Michael Wolthuis]

Not sure this will help anyone else, but I got my devices working tonight, but not sure how….

 

I was able to cat both the tty and the cu version, but only when the device showed NOT CONNECTED on Bluetooth.  As soon as it said NOT CONNECTED, boom, data….  Say then worked in QTH.  On MAC OS, it literally shows my devices disconnected, but then they work.  If I connect them, they stop working.

 

This makes no sense to me at all….  It is repeatable after a reboot.

 

Hmmmm…. OS issue I think, but not sure what yet.

 

Mike

 

 

From: Weston Bustraan <wbus...@gmail.com>
Date: Friday, January 7, 2022 at 9:00 PM
To: Michael Wolthuis <wolt...@gmail.com>
Cc: qthapp-users <qthapp...@googlegroups.com>
Subject: Re: Anyone have the issue where SPP device doesn't show up?

 

I am able to on my X1C5, but keep in mind that if there are no incoming packets, you won’t see any KISS data. I have mine configured to send GPS data over Bluetooth as well, so at least I see the NMEA sentences every second. That’s a good indicator that the serial connection is working

[Weston Bustraan]

Ok, I think I have a theory as to what might be happening. I think that when the Bluetooth status in System Preferences shows "Connected" it is that macOS itself is trying to use the device for its own purposes. Given that it's a serial connection, I would suspect that macOS might be attempting to use it as a modem to start a dial-up session. That would explain some of the other symptoms. While macOS has the port open, no other application, like QTH or cat can access it. It also explains why only the cu.* device is affected; macOS would naturally use the callout device, leaving the tty device still usable.

I tested the connection to the X1C5 under Big Sur and Monterey. Under Big Sur, I can double click as much as I want and it never goes to "Connected". Under Monterey, it goes to "Connected" for about 30 seconds and goes back to "Not Connected".

- Wes W8WJB

[Michael Wolthuis]

That makes some sense with what I am seeing, I just can’t keep it consistent.  This morning, turn the devices on, I guess I should connect them from the OS menu bar, but now they stay connected, no data flow…

 

I’ll keep playing….

[Michael Wolthuis]

So, a little more data…. This morning, to get it to work, I had to remove the connection (not just connect it), re-connect it, then it turned back to gray and data started flowing.

[Weston Bustraan]

I don’t think you want to connect the Bluetooth ports via the macOS UI. Just leave them disconnected. The OS will automatically establish the connection when an app like QTH attempts to read from and write to the port.

- Wes W8WJB

[Michael Wolthuis]

Ohh ok, didn’t realize it would do that, I will try that.