The latest firmware has a new option (X_EnforceRequestUserID ) to help fight against a problem commonly known as "ghost calls", where a machine/hacker may be scanning for SIP devices. This new option will enforce that the SIP INVITE received by the OBi device must have a request userid that matches the SIP account ID as configured on the device. Older firmware does not enforce this behavior. Most service providers should be compliant to this behavior, so that it will be a lot harder for a hacker to scan for SIP devices. But for those who are not, the X_EnforceRequestUserID parameter should remain unchecked (disabled).
To continue to use the old behavior, follow these simple steps:
1. Open your OBi device web page (from web browser, enter IP address of the device. You can dial ***1 to listen to the IP address of your OBi)
2. Navigate to the SPx Service Page (x=1,2,3,4), and uncheck this option: X_EnforceRequestUserID
3. Press the Submit button on the page, and reboot the device by selecting the reboot button.
Thank you – Obihai Support