We have got a sat phone (Iridium Go) as a bit of research. There are some technical improvements on the cards for Iridium coming along soon which will make it an interesting option, albeit expensive, for some broadband cases. But for now it is partying like it is 1989 with 2400bps data calls (no, I did not miss a "k" or "M" there), phone calls, and texts. It does, however, work, and can even be told to send GPS update texts periodically as this device also has a GPS. Yes I have made a tracking app with google maps and so on.
I'll post more on this, and using Inmarsat and mobile roaming data in a little over a month. For now we are just getting started and testing. One of the staff is doing an antarctic expedition at Christmas, and that will be a very interesting use of this.
When testing calls from the phone I was a tad surprised to find the CLI was wrong. My number is +881622490112, and I would expect to be presented as that or 00881622490112 on a phone I called.
However, calling Three, and EE got me 001881622490112 and calling landline got me 0881622490112. Both of these are obviously wrong.
So the tech support journey begins.
1. I tell them that calling Three and EE get the 0018816 version and landline gets 08816 version
They ask for details of the test calls I made, times, called numbers, CLIs shown. Vaguely sensible request.
2. I tell them times and called numbers and presented CLI as requested.
They ask which carriers each call is with? Well, I said that in the first place and they can tell from the numbers, but what the hell!
3. I tell them which carrier it is for each as requested, again.
They say, and I quote: "I don’t understand the problem. Please advise." !
4. I explain that the CLI is wrong, as per the subject line! How simple can you get?
They say, and I quote: "The numbers are technically correct." (yes, the best kind of correct, I know).
WHAT?!?!? I am sorry but they are not!
They say that they aren't being translated correctly on the Mobile providers[sic] end. That is not really a good answer as no translation is needed, and in fact a "1" has been inserted which is not a translation you would ever do.
But Iridium are losing money on this!
I don't understand why they seem not to care. If I were Iridium I would be making damn sure the CLI was right everywhere because that way people could call back when a sat phone user has called. Calling Iridium is £3.60 a minute (from BT) so you would want people to try and call back. Anyone trying to call me back gets a dentist in America!
Anyway, next trick is to contact the mobile providers and ask why the CLI is wrong. But seriously, Iridium are crazy if they are not on top of this.
Update: Power of the blog! they are making test calls and trying to sort this.
Update: Their test calls all worked but real calls are just the same!
If you would like to get in touch with me you can send a call to us and I can capture the SS7 UK-ISUP trace so you can see exactly what is wrong. I could even raise a signalling fault with BT for them to pass on :P
ReplyDeleteThat would be great - Alex has it this weekend, but I'll see if he can get you on IRC. Their tech support won't know what hit 'em!
DeleteI've had the occasional spam caller pop up with strange/invalid CLID (rather than the more common withheld/unavailable which will be going to the bitbucket as soon as I get it plumbed in). Often of the form +1... (with too many digits after the 1 to be genuine NANP numbers).
ReplyDeleteThere was a "0441..." at least once in the past too - a butchered UK number I think. It seems surprising how frequently CLID gets mangled, for what should be quite a simple core function!
If only network providers blocked invalid CLIDs...And then started some sort of validation ("oh, you are presenting an 0870 number outbound, before we'll allow that we'll check that number is allocated to you") and then other providers can assign "trust levels" to those providers ("yes, AAISP always send validated CLIDs, but 'scam artists Ltd' very rarely do") and then offer a blocking system...
ReplyDeleteOh - I forgot, BT/Virgin et al receive money for each call over their network so what incentive is there to improve customer service/happiness by blocking obvious invalid calls.
I get the feeling no-one really cares if CLID is right or wrong.
ReplyDeleteRecently investigated fraud on a phone system. Someone was calling in out-of-hours using a faked CLID of an international call forwarding service.on a premium rate number and then leaving a voicemail, calling back and (due to insecure setup of the phone system by the telephone leasing company) logging into the mailbox and using the callback feature. Then would spend hours and hours on the phone to wherever the call was forwarded to.
DeleteNobody was interested in tracking down how or what was done to allow the fraudulent caller to spoof their caller id.
My understanding is that part of the "voicemail cracking" newspaper scandal was done by spoofing the CLID of the mobile phone you wanted to access the voicemail of and dialing into the MNO's voicemail system, which checks the CLID and immediately provides unauthenticated access to the voicemail.
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