T53 - EXP50 - EHS40 - no sound on hookup

[y.sakref]

Hello everyone,

I'm actually working with end-user who use these configuration :

SIP T53 : Firm --> 96.86.0.45
Expansion Module EXP50 : Firm --> 1.0.1.8
EHS40 module : Firm --> 1.0.0.1
Sennheiser - D10 BS Phone EU
Connected in the same order as the list.

The probleme is when someone call that user, the user with the headphone do not hear the user, the only way to make it work is to activate the speaker and reactivate the headphone.

The problem do not show when disconnecting the EXP50 expansion module.

For sur I test the headphone on multiple differents SIP model phone and the problem does not come from the headphone as the problem happen with an other headphone on the same phone, and multiple user having the same configuration in the office experience the same problem.

The phone where in version firmware 96.86.0.45 and pushing the new firmware 96.86.0.70 was not changing anything.

Does anyone experience same problem ? do i have found a bug or is it just because the headphone is not compatible with the EHS40, EXP50 and SIP-T53 phone ?

Thanks for the support and your return about this problem