I think you would, or something like it. I run remote extensions on a smartphone and a tablet. I havn't used a VPN, neither do they connect directly to my home system. They connect via a free hosted Asterisk server and there is a virtual tie line between that, and my system.
Someone on the "Electronics_101" mailing list came up with an interesting idea a week or so ago. (Sorry I didn't keep the email).
It was a little circuit that would automatically break the connection of an incoming call after a second or so then reset.
The thinking was that a genuine caller would think "Oh" and re-dial, whereas an automated dialer used by these nasty little toe-rags would just move on to the next number in its list.
I didn't look into it so I'm not sure of the timings or anything like that. I'm not even sure if you could connect something like that to a BT line bearing in mind "approvals" etc..
That is like "greylisting" in spam filtering. It could be extended to only do it for anonymous calls, or for numbers not yet in some dynamically built whitelist (numbers that have called recently).
It probably works, but of course the calling persons have extra costs. (assuming their subscription plan charges for answered calls)
Yeah - rereading it there didn't seem to be a clear bit of hardware which would do call answering/interception and had been used successfully by a poster; most of the stuff being targeted at SIP gateways.
I think I side lined it because it was all becoming too complicated.
This time round there seems to be a ready made solution with hardware
to be potentially more flexible if more expensive.
[I note that Broadband Buyer has now replaced it with the Cisco SPA3102.]
Still not entirely sure about using the Linksys/Cisco solution anyway because the reviews suggest it is a steep learning curve.
When you do, ping me on uk.telecom.voip, I have an SPA3000 (available at 20GBP delivered from Ebay sellers) and a couple of PAP2 talking to Asterisk on a Raspberry Pi.
I have a Nettalk unit which has run out of time and I might try taking it apart. I've wondered how they can generate ring tone and line voltage in such an inexpensive module. They sell a year of service for $30 and the unit with a year of service for $50. That's just $20 for the unit. What I think you guys are looking for is something like this unit without the CPU and network interface, no? I would be interested in making a module like this if I can put it together cheaply enough.
The PAP2T was the old Cisco box that did the same job: plug into a phone socket on one side, get usable VoIP out of the other. I don't think they've made them for a while, though they still show up on eBay and such.
Personally I use a PCI card with telephony module in a PC running Asterisk, but that's not appropriate to discussion of a Pi. (I will also see questions on uk.telecom.voip.)
A VOIP analogue telephone adapter (ATA): turns a normal landline phone into a VOIP device. There are lots of them about as they're cheap and they were given out by landline-replacement phone companies like Vonage. Some of them are locked, which is a pain to reverse.
They're getting on a bit now, I don't know what the modern-day equivalent is.
There are also of course the Siemens Gigaset DECT phones which are both landline and VOIP phones. The DECT base station has a Web GUI to configure it for VOIP services. You can select whether to use landline or VOIP when you make a call (with the default configurable to be either).
The main difference between the SPA3000/SPA3102 and the PAP2/SPA112 is the latter devices have no FXO port for a regular exchange (CO) line, instead they have a second FXS port for a regular POTS telephone.
I have one of each type in service at the moment.
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It has occurred to me that my Pi has long since paid for itself simply because of the electricity that its headless desktop PC predecessor used.
Now I know what a PAP2 is, I know I don't want one. What I do want is something that can splice something into a PSTN connection analogously to an answerphone box so that it can look at the caller and accept it or not [*] and also act as an answerphone. It sounds as though an SPA3000/ SPA3102 plus an RPi running RASPBX should be able to do that.
[*] probably by checking that the number is valid and/or by looking up a blacklist - does anybody know if I can get a copy of that from the PRS? Is there a safe way to check a number's validity?
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martin@ | Martin Gregorie
gregorie. | Essex, UK
Andrews+Arnold (copied) were running a free honeypot line you could direct it to using SIP VoIP. Not sure if that's still going (it is still available for their VoIP customers to use).
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Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
They are free when used by landline phones. I guess the reason for using one here is that when you divert an incoming call you pay for the ongoing call. (That is an assumption, which may be wrong. If it is wrong, then divert to an expensive 09 number.)
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Alan Adams, from Northamptonshire
alan@adamshome.org.uk
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