Simultaneous calls on one sip account

I have a Grandstream GXP280 sip telephone, which supports 1 SIP account. It is said that it supports two lines though, so one should be able to switch between calls on the same SIP account.

I tried this by calling to our DID, and picking up with the phone. Then I tried dialing the extension with an other phone inside the network. This gives me the busy tone though.

In my sip.conf I added busylevel and call-limit to the template of the receiving phone. This didn’t seem to help though.

[stumpel-zwaag](!)                              ; create template for our devices
type=friend                                     ; the channel driver will mathc on username first, IP second
context=StumpelZwaag                            ; this is where calls from the device will enter the dialplan
host=dynamic                                    ; the device will register with asterisk
;nat=yes                                                ; assume the device is behind nat
secret=x                              ; a secure password for this device
dtmfmode=auto                                   ; accept touch-tones from devices, negotiated automatically
disallow=all                                    ; reset with voice codecs to accept from, and request to, the device
allow=alaw                                      ; which audio codecs we accept from
busylevel=2                                     ; twee inkomende gesprekken

Any idea’s?

Although i dont know this phone exactly, I do know that not all phones enable “call waiting” by default. Its possible that the phone is sending back a busy here.

See what the asterisk CLI has to say, it should be easy enough to see. At the command line:

This will run the CLI (command Line Interface), showing the progress of all the calls and responses.

You will need some v’s as well, or to explicitly set the verbosity, somewhere.

Unless something has changed recently, simple Asterisk configurations will offer any number of parallel calls to a phone.