Connect PM5 to both phone and watch

[Simon G]

Dear all,
I'd like to connect my RowErg PM5 monitor to my watch (Coros Pace 2 where all my activities are tracked, bike, workout, swim, run) and to my phone to participate to ErgData challenges and get the full history on the app.
I currently cannot have one training Sync with both devices, any help ?

[Sakly]

Bluetooth is a 1:1 connection, so you can connect your phone OR your watch, but not both at the same time using Bluetooth.
I use a Garmin watch, which can receive PM5 data via Ant+, this works independently from BT connections. Ergdata connection done via BT, watch connected via Ant+, so both devices get all the data.

Don't know if Coros supports this as well.

[JaapvanE]

Bluetooth is a 1:1 connection, so you can connect your phone OR your watch, but not both at the same time using Bluetooth.

Indeed, but I'd like to add a little nuance. Most bluetooth devices actually allow multiple BLE connections. For example, my Garmin dual HR allows two simultaneous BLE connections. It is a design choice from Concept2, either to save battery or to prevent conflict handling.

I use a Garmin watch, which can receive PM5 data via Ant+, this works independently from BT connections. Ergdata connection done via BT, watch connected via Ant+, so both devices get all the data.

Yeah, and ANT+ is a broadcast protocol. so it allows unlimited listeners.

Don't know if Coros supports this as well.

It depends on the specific watch type. Some Coros watches do, some don't.

[Sakly]

Bluetooth is a 1:1 connection, so you can connect your phone OR your watch, but not both at the same time using Bluetooth.

Indeed, but I'd like to add a little nuance. Most bluetooth devices actually allow multiple BLE connections. For example, my Garmin dual HR allows two simultaneous BLE connections. It is a design choice from Concept2, either to save battery or to prevent conflict handling.

Sure, there are devices handling multiple connections via BT, but in the end a target device can only receive a single data point from one or the other connected device. Multiple connection would only be helpful, when the main actor (aka PM5) only provides data, but does not receive data.
Better example to understand: most BT loudspeaker support multiple connections to receive data, but only one of the connected devices can play music at a time. The other device can interrupt at any time and stopping playback from the first device. I don't get the point of this feature, to be honest

[JaapvanE]

Sure, there are devices handling multiple connections via BT, but in the end a target device can only receive a single data point from one or the other connected device. Multiple connection would only be helpful, when the main actor (aka PM5) only provides data, but does not receive data.

O darn, with ESPRowingMonitor we implemented just that for a maximum of three devices.

First of all, within Bluetooth you subscribe to specific characteristics. So, one can actually differentiate between the different roles (just listening, or also control). So ifyou want a single source of command, one could force that on a much more granular level of the characteristic (which we don't).

Aside that, conflict handling isn't that difficult. On its bigger sibling OpenRowingMonitor we accept commands via the user interface, BLE and MQTT. No issue with multiple command sources (one will be direct, the other app based, the other home automation based). So I can tell Alexa to set up my rower for a 10K session. But I can adjust it via ErgData or the GUI. Our resolution strategy is easy: last one wins. Based on that, we report all metrics and the clients will find out the real plan.

BLE actually has a broadcast/multicast variant as well, so a lot is possible if people are willing to keep up with current standards.

Better example to understand: most BT loudspeaker support multiple connections to receive data, but only one of the connected devices can play music at a time. The other device can interrupt at any time and stopping playback from the first device. I don't get the point of this feature, to be honest

Allowing multiple devices to listen to the same metrics stream is extremely usefull for a PM5. People want to connect ErgData for recording, connect to a game, connect to a watch.

Having multiple remotes can be usefull. There are actually quite some interesting scenario's that involve multiple BLE connections controlling a device.

[Simon G]

Thank you all for your input
Coros Pace 3 is not supporting Ant+ (while pace 2 does ...)
So i prefer to link the phone to participate to concept 2 challenges, April 15th will be tough
Bye

[JaapvanE]

Come to think of it, you can download your workout from the C2 log as fit-file, which you might be able to import in a Coros environment. Not optimal, but it might help with keeping workouts in one place.