Can I patch my cell earphone jack to power a Siemens hands free amplifier kit?

I think I am trying to accomplish something that is electronically flawed
(or downright stupid)-- need advice.

I currently have a Siemens s46 cell phone which goes through a modified
Siemens hands free car kit. A custom Siemens cable goes from the phone to
the Siemens car kit which drives the hands free Mike and the speaker output.
Everything works fine.

I am replacing the s46 with a Blackberry which has no equivalent kit -- only
a corded hands free earphone/mike connected by a 2.5 mm jack.

To make a long story short, I patched a new 2.5mm jack and cable to connect
the earphone audio out from the BB to (what I believe) are the audio input
wires on the Siemens car kit circuit board (which previously were sourced
from the Siemens cell phone by custom cable).

Result: hum, clicking, no phone. Questions:

1. Is this a level problem; i.e. the audio out of the Siemens phone is much
higher than the BB earpiece out
2. Is there some other complexity in the Siemens arrangement that I'm not
duplicating (signal from phone to turn amplifier on, etc.)
3. Is this simply a very bad idea (most likely)

Thanks in advance for any help. Glad to provide additional information if
that would help.

KC

 

Probably not compatible and you may damage the Motorola Blackberry Device in
trying.