The SIP client has connected to the PABX, but there is no audio when I make a call?

This can be a codec problem.

SoftRadio SIP client can use G711u or G711a, which all SIP equipment must support according to the standard.

Since we use G711u coding internaly in Mimer SoftRadio, that is the one our SIP phone will prefere for a connections.

Please check the codec settings in your PABX.