# OSD says "Waiting for MAVLink Heartbeats" when attached to TELEM 2 port

**URL:** <https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306>\
**Category:** Uncategorized\
**Created:** [January 16, 2024, 7:28am UTC](https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306 "2024-01-16T07:28:12Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![hal](https://discuss.px4.io/letter_avatar_proxy/v4/letter/h/ee7513/32.png) [@hal](https://discuss.px4.io/u/hal)\
**Post date:** [January 16, 2024, 7:28am UTC](https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306/1 "2024-01-16T07:28:12Z")

</div>

My OSD works when attached to TELEM 1. When I attach it to TELEM 2 and set the MAVLink parameters to the same as TELEM 1, it just says “waiting for MAVLink heartbeats” on the OSD.

The Parameters I have set are:  
MAV\_1\_CONFIG = TELEM2  
MAV\_1\_MODE = OSD  
MAV\_1\_RATE = 57600 B/s

These are all the same settings I have for MAV\_0 instance, except MAV\_0\_CONFIG = TELEM 1.

Does anyone know why the OSD will only work in TELEM 1?

I am using Pixhawk 6C mini with PX4 1.13.3

---

<div class="post-metadata">

**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [January 16, 2024, 8:31pm UTC](https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306/2 "2024-01-16T20:31:26Z")

</div>

I think you have mixed up the param RATE for baudrate. The rate needs to be max 1/10 of the baudrate. And the baudrate needs to be set using SER\_TEL2\_BAUD (or something similar).

---

<div class="post-metadata">

**Author:** ![hal](https://discuss.px4.io/letter_avatar_proxy/v4/letter/h/ee7513/32.png) [@hal](https://discuss.px4.io/u/hal)\
**Post date:** [January 18, 2024, 6:07am UTC](https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306/3 "2024-01-18T06:07:20Z")

</div>

Hi @JulianOes  
Thanks for your reply.  
I have set the parameters as you said and that unfortunately hasn’t worked.

Attached are screenshots of my parameters page on QGroundControl.

I set SER\_TEL2\_BAUD to 57600 and the MAV\_1\_RATE to 1/10 of that (5700). The OSD still says “Waiting for MavLink Heartbeats” when plugged into TELEM 2.

It works fine in TELEM 1 and the MAV\_0\_RATE and SER\_TEL1\_BAUD are both set to 57600. (Although I cant get flight mode to display)

Thanks.

![image](https://discuss.px4.io/uploads/default/original/2X/4/41e3dae7bcb03c9c3f5ca6f2d5448945bb6386d2.png)  
 ![image](https://discuss.px4.io/uploads/default/original/2X/f/f5da79c3b1795f0940e2e4003131ce15229f1780.png)

---

<div class="post-metadata">

**Author:** ![JulianOes](https://discuss.px4.io/user_avatar/discuss.px4.io/julianoes/32/30_2.png) [@JulianOes](https://discuss.px4.io/u/JulianOes)\
**Post date:** [January 18, 2024, 10:38pm UTC](https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306/4 "2024-01-18T22:38:53Z")

</div>

Try disabling flow control.

---

<div class="post-metadata">

**Author:** ![hal](https://discuss.px4.io/letter_avatar_proxy/v4/letter/h/ee7513/32.png) [@hal](https://discuss.px4.io/u/hal)\
**Post date:** [January 20, 2024, 5:10am UTC](https://discuss.px4.io/t/osd-says-waiting-for-mavlink-heartbeats-when-attached-to-telem-2-port/36306/5 "2024-01-20T05:10:23Z")

</div>

Thank you that solved it. 🙏