Attended Transfer - Consumes 3 Simultaneous Calls?

[dRoo]

We were having trouble transferring a 3rd customer to another staff member, though we have a licence for 4 calls.

It seems that while we are talking to three customers we consume 3 calls, i.e.
#1 Talking - Customer 1 - Staff 001
#2 Talking - Customer 2 - Staff 002
#3 Talking - Customer 3 - Staff 003

But when staff 003 tries to do an attended transfer to staff 004 the following is added to the active call list:
#4 Routing - Staff 003 - Staff 004

Then when staff 004 tries to pickup the call, the following is added to the list
#5 Initiating - Staff 004 - Staff 003

Resulting in 5 active calls, and Staff 004 receives verbal warning 'call limit exceeded' or something to that effect.

I can understand that an attended transfer may take up an extra line for the internal conversation, but why 3? I don't feel like this is how it behaved before though I can't be sure. Am I doing anything wrong? Is this behaviour correct? Obviously I could do a blind transfer instead and that would work, but that's not how we operate.

• 3CX Version, e.g. Professional Annual 18.0 (Build 461)
• Server OS, ?
• Is the 3CX Server Hosted and where? Hosted (in 3CX?)
• IP Phone Make/Model/Firmware version, WebClient. Windows App.
• Provisioning Method: ?
• Trunk Provider or VoIP Gateway Make/Model, ?
• Has the Firewall Checker passed: ?
• Are custom Phone Templates being used: Don't think so

 

[ChrisC_3CX]

Attended transfer will not consume 3 calls unless you are transferring the call to the 3CX Mobile client which will case this but only for an instance while the call to the mobile client is being established.

Can you double check and confirm what 3CX endpoints all three involved parties are using and who is using what? For instance, transferrer using windows app, transferee using webclient, final destination/callee using mobile client, etc.

 

[dRoo]

Transferrer 003 using web client, final destination 004 using web client, transferree is the customer using their mobile. I think I've got that right.

003 and 004 do also have 3cx mobile client on Android but this is not what was being used or picked up on. But the mobile client would ring and just remain unanswered.

 

[ChrisC_3CX]

I have looked into this further and can confirm that if the final destination (extension receiving the transfer) is either a 3CX Webclient/PWA or 3CX Mobile client this behavior is expected due to the use of PUSH. This is due to the fact that the use of PUSH momentarily requires an additional sim call to complete the call hence the message you get when you only have 1 sim call available while attempting an attended transfer to either of these clients.