Voice conference call - PIN number problems on using German phone number

Hello,

We use your Conference Call system from different countries since long time and without problems.

Since few weeks, if we call the German number +49 1805 009320

from Dubai/VAE

then it is hardly possible to enter the PIN number. Many digits are counted double even if we press only once.

For example:

PIN = 12345678

Then the computer voice says: You entered 112334566788

 First we thought about

- broken telephone -> have same effect with different phone inside our premises

- shivering hands -> same effect with three colleagues and only since few weeks

Then we tried the US conference number from Dubai, +1 213 2893427

With this number it works perfectly from

- same both phones

- with same colleagues

My system details (OS etc):

Polycom (Conference room spider)

Alcatel-Lucent office phone

all IP-based

License: company licence, do not have it at hand