Thanks for correcting. I took Paul’s initial post about the Gigaset the wrong way-thinking either the HSP or HFP protocols would be sufficient, but the Panasonic base uses HSP and Phonak HA’s use HFP.
I haven’t had any problems with either my cell phone or our landline and the Panasonic model we own. But then our “landline” was an AT&T Home Cellular Phone (connects to a cell tower for its “landline” connectivity) and for the longest time we had it connected to an AT&T Microcell (connects to the Internet for VOIP Internet calling, better connection than that to a distant cell tower). The particular Panasonic unit we have can be cranked up to a plenty loud volume, either using my cell phone or the cellular landline, while we maintained it.
Here’s a link to Phonak’s instructions on what’s required to pair to a BT-enabled landline phone. It specifically mentions the HFP requirement and specifically mentions that HSP won’t work.
Connecting Phonak hearing aids to a Bluetooth landline phone
Edit_Update: The plot thickens. In the Panasonic manual that I linked in my previous post, it says (effectively) that my Panasonic cordless handset supports both HFP and HSP. The HFP protocol is used to link the base unit to cell phones, the HSP for BT headsets. Pairing is initiated for either cell phones or BT headsets by entering a specific key code. Theoretically, if you entered the keycode to pair with an HFP-capable BT cell phone, you could pair the Panasonic base with Phonak HA’s. But I think the problem would be one of directionality. When using the HFP protocol to connect to a cell phone, the Panasonic system is the client (akin to being a BT headset, allowing one to hear and transmit voice to the cell phone to go back out over the network) whereas when using a BT headset paired to the Panasonic base, the BT headset is the client (slave) and the Panasonic phone the master sending or receiving any voice communications via its connection to the landline.