"On the Phone" or "User Busy" status display into caller phone LCD

[ugo.viti]

Hi,

I'm wondered if this feature is already implemented, but I haven't found an answer, so I'll asking here.

Suppose the following scenario:

Involved Users:
201
202
203

Call flow:
- all users have Call Waiting enabled.
- 201 call 202
- 202 answer to 201
- when 201 is on the phone with 202, 203 call 201
- 201 hear the background call waiting tone, and into yealink display can see the call coming from 203
- 203 hear the ringing tone, but it can't figure out that 201 is already on the phone
- 201 can't answer to 203 because the call with 202 is very important
- 203 after some time giveup the comunication thinking that 201 is not in office

the question is:

Exist a way to show a message into 203 LCD that 201 is already occupied into another conversation?

I seen this features into 3com phones connected to 3com PBX, and that phones display "On the Phone" message status into caller LCD.

I'm trying to accomplish that feature using T26 phones connected to Asterisk 1.8.15 PBX.
Of course using the BLF keys is not the solution.

Thank you very much for the support.

Best Regards