BLE download from Heinrichs Weikamp dive computers

Dirk Hohndel dirk at
Thu Jun 29 07:37:13 PDT 2017

On Thu, Jun 29, 2017 at 02:19:25PM +0200, Jan Mulder wrote:
> On 28-06-17 23:25, Linus Torvalds wrote:
> > On Wed, Jun 28, 2017 at 1:52 AM, Jan Mulder<jlmulder at>  wrote:
> > > So, there is some communication, and with my very very limited knowledge on
> > > BLE, it seems that the correct service is detected (Found service
> > > "{53544d54-4552-494f-5345-525631303030}" and things finally seem to fail
> > > with something encryption related? If needed, i can produce screendumps from
> > > Nordic to see what BLE things are visible on the OSTC3, but I suspect that
> > > most of the required data is in the log above.
> > Yeah, most of it is there, but it would be good to see what the Nordic
> > RF app says about those value handles that are inside the vendor
> > service.
> 5 screenshots are attached. While I first thought that the correct service
> was detected,  I know think it is the wrong one. From the HW doc (,
> we can see that the OSTCs "use Bluetooth chipset creates a virtual COM port,
> with Bluetooth 4.0 (LE) the device is compatible to “Stollman's Terminal IO
> Profile”. I am almost sure that the used hardware component is the
> BlueMod+SR (Telit, formerly Stollman).
> From
> we can learn from section 6 that the  Terminal I/O Service has UUID: 0xFEFB.
> So, that very likely corresponds to the service  UUID: Stollmann E+V GmbH
> (0000fefb-0000-1000-8000-00805f9b34fb). This service has 4 characteristics.
> In order to check my hypothesis, I hacked around in qt-ble.cpp. And yes, I'm
> basically sure that the service 0000fefb... is the right one. In the code in
> master this one is discarded as standard, but by using this anyway I am able
> to get the OSTC3 in download mode. I did not succeed up to now to receive
> data from the OSTC3, so obviously, the parsing fails right at the start.

One of the coolest things about working with Heinrichs Weikamp dive
computers is that Matthias is on this mailing list and usually responds to

Matthias, can you confirm that 0000fefb-0000-1000-8000-00805f9b34fb is the
UUID we should be connecting to? Is this a fixed UUID or does it ever
change? Any special tricks we need to get data back from the dive

> > So I do think that I'd want to see that full descriptor layout that
> > the Nordic app is so nice about (make sure it's fully expanded), and
> > if possible a bluetooth packet dump of a download if there is some
> > dive log software available that uses BLE.
> I looked around for any dive log software for the OSTC family, but I get the
> impression that Subsurface is leading here, so no BLE capable stuff found
> that can act as a reference.

Also a question to Matthias - what software is the reference for BLE


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