If you imagine your isdn circuit, you can only send cli if it is a number registered on that circuit.
To be able to send the cli of the caller, this would mean over your isdn circuit you need to be able to pass anything as a cli, correct? Understand so far?
So if you could do that, what would stop me sending a charity number as a cli, pretend to be that charity and collect some credit card details etc.
You cannot do it.
The send callers cli thing for mobile twinning is for when you have a private type mobile network.
In the UK BT have something called mobex whereby BT provide you with a PRI into the BT mobex (mobile) network. You can call from mobile to mobile on ext numbers rather than the full moby number. You can also make and receive moby calls as normal. So in effect this mobile network is private between the IPO and the mobiles but public in every other aspect.
Because it is a private network between the IPO and the handset, you can send any cli to the mobile handsets.
Does that make sense?
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