Write fails with QSerialPort

[wspilot]

Hi,
ububtu 12.04
Qt 5.1.1
I am trying to write a character to the serial port with QSerialPort, but I get no response from the device.
@qDebug() << "nr of btes written:" << serialBaro.write("a");
if (! serialBaro.isWritable() )
{qDebug() << "baro not writeble!!";}//is OK
if(! serialBaro.waitForReadyRead(100))//NOT OK, should get response as with boost
@
While using boost::asio (older version) writing goes OK, so the device is working correctly:
@ baro.writeString(string("a"));
baro.setTimeout(boost::posix_time::millisec(100));@

[wspilot]

Just found out. QtSerialPort does also work on the (boost version) notebook.
The only difference between current laptop and the notebook is ubuntu version: resp 12.04 and 11.10.