# Serial Connection Problem **URL:** \ **Category:** MAVSDK\ **Created:** [July 16, 2018, 4:26pm UTC](https://discuss.px4.io/t/serial-connection-problem/7166 "2018-07-16T16:26:26Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![gexlenter](https://discuss.px4.io/letter_avatar_proxy/v4/letter/g/f14d63/32.png) [@gexlenter](https://discuss.px4.io/u/gexlenter)\ **Post date:** [July 16, 2018, 4:26pm UTC](https://discuss.px4.io/t/serial-connection-problem/7166/1 "2018-07-16T16:26:26Z")
Hi, I used DronecodeSDK::add\_serial\_connection() and it returned a success message. However, when I tried .system().isconnected() it returns false and system\_uuids().size() returns 0. What could be causing this problem? I am connecting to a pixhawk & Windows 10 for context. The serial port is working fine on an older version of QGC, but it fails to work in the latest QGC (similar to [Problem in connection with QGC - Access port cannot create](https://discuss.px4.io/t/problem-in-connection-with-qgc-access-port-cannot-create/4856)) which I believe uses Dronecode? # OUTPUT connect: Success [12:21:09|Debug] New: System ID: 1 Comp ID: 50 (…\dronecode\DronecodeSDK\core\dronecode\_sdk\_impl.cpp:292) [12:21:09|Debug] Component Unsupported component added. (…\dronecode\DronecodeSDK\core\system\_impl.cpp:339) system\_uuids().size(): 0 ---
**Author:** ![DonLakeFlyer](https://discuss.px4.io/user_avatar/discuss.px4.io/donlakeflyer/32/3036_2.png) [@DonLakeFlyer](https://discuss.px4.io/u/DonLakeFlyer)\ **Post date:** [July 16, 2018, 9:23pm UTC](https://discuss.px4.io/t/serial-connection-problem/7166/2 "2018-07-16T21:23:29Z")
How are you connected? SiK Radio or direct USB? ---
**Author:** ![DonLakeFlyer](https://discuss.px4.io/user_avatar/discuss.px4.io/donlakeflyer/32/3036_2.png) [@DonLakeFlyer](https://discuss.px4.io/u/DonLakeFlyer)\ **Post date:** [July 16, 2018, 9:24pm UTC](https://discuss.px4.io/t/serial-connection-problem/7166/3 "2018-07-16T21:24:07Z")
Also I assum you installed the windows driver? ---
**Author:** ![gexlenter](https://discuss.px4.io/letter_avatar_proxy/v4/letter/g/f14d63/32.png) [@gexlenter](https://discuss.px4.io/u/gexlenter)\ **Post date:** [July 17, 2018, 5:15am UTC](https://discuss.px4.io/t/serial-connection-problem/7166/4 "2018-07-17T05:15:36Z")
I am connecting directly by USB. I have installed the driver but I am not sure if it is the correct one. Downloaded from ([http://pixhawk.com/static/px4driver.msi](http://pixhawk.com/static/px4driver.msi)) ---
**Author:** ![DonLakeFlyer](https://discuss.px4.io/user_avatar/discuss.px4.io/donlakeflyer/32/3036_2.png) [@DonLakeFlyer](https://discuss.px4.io/u/DonLakeFlyer)\ **Post date:** [July 17, 2018, 4:06pm UTC](https://discuss.px4.io/t/serial-connection-problem/7166/5 "2018-07-17T16:06:19Z")
If you install QGC it will ask to install the driver if it is needed. I assume that is the same one that is on the QGC installer though. ---
**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:** [July 20, 2018, 9:35am UTC](https://discuss.px4.io/t/serial-connection-problem/7166/6 "2018-07-20T09:35:55Z")
> [@gexlenter](#): > > [12:21:09|Debug] Component Unsupported component added. (…\dronecode\DronecodeSDK\core\system\_impl.cpp:339) This means the component ID chosen is not supported. If this is an autopilot, try using the component ID 1. You can set this using: `MAV_COMP_ID` to 1. Component ID 1 stands for `AUTOPILOT1`, see: [http://mavlink.org/messages/common#MAV\_COMP\_ID\_AUTOPILOT1](http://mavlink.org/messages/common#MAV_COMP_ID_AUTOPILOT1). ---
**Author:** ![roomez](https://discuss.px4.io/user_avatar/discuss.px4.io/roomez/32/5483_2.png) [@roomez](https://discuss.px4.io/u/roomez)\ **Post date:** [August 2, 2021, 9:56am UTC](https://discuss.px4.io/t/serial-connection-problem/7166/8 "2021-08-02T09:56:02Z")
Hi @JulianOes How Change this parameter MAV\_COMP\_ID ? i can not connect to qgc because change MAV\_COMP\_ID.