Toggle Mobile

[inquisitor]

Originally Posted by andy

This isn't about call diversion from the Toggle SIM itself, but the ability to forward other numbers to it?

Does diversion rely on getting permission from the destination number network, and that can be turned down?

The SS7 protocol which is used for interconnection among carriers has a forward sequence number (FSN) and a forward indicator bit (FIB) by which the originating carrier discloses to the terminating carrier that a call is being forwarded and also from which phone number the call is actually originating. The main purpose of this information is that the terminal of the receiving party can indicate forwarded calls as such enabling the end user to distinguish between regular and forwarded calls (you might have noticed that your mobile phone indicates forwarded calls and displays the original callers number instead of the forwarding line's number).
Toggle unfortunately uses this information to block calls that are flagged as forwarded. I guess the reason for the blocking of forwarded calls is that they try to avoid assymetric call volumes where incoming calls outweigh outgoing ones since they obviously don't earn much from free incoming calls given today's low mobile termination rates in most markets. Toggle's business model very likely relies on a sound amount of outgoing calls and so they probably try to avoid too much incoming calls by blocking forwarded calls. Though the current blocking rules seem to be a bit inconsistent.
In any case when you set up the forwarding through your own VoIP equipment there's no FSN or FIB that may reveal forwarded calls since the FSN or FIB can only be added by the exchange and not by the user terminal. Hence I can still forward all my VoIP numbers to my toggle SIM through intervoip.com (a Dellmont brand) using my FritzBox. Problems start when you let your carrier forward calls in the exchange.