What is the Best IOS and Android SIP app to use with FlyNumber?
We really like Groundwire from Acrobits
You can keep the app completely off ( not running in the background ) and with their push technology still receive calls- big battery saver
Its a paid app but well worth the price, its stable and comes with many features
Can you set a different ringtone for the Fly Number Account that Co exist on same iphone with a regular phone line?
With the Groundwire app yes, it works with the built in IOS phone and ringtone is different ( can be changed)
Any point using the Phone systems app?
It's directly from PXBww/Phone systems.
Yes there is, many users enjoy the ability to change the outgoing caller ID's at a whim using the apps' GUI ( user interface)
Ok. But I have the feeling this app works only with a Phone system SIP account installed as "Device", right?
Can't work with a custom SIP account?
Yes thats correct, the app would only work with our SIP