Hayling Island

Hayling Island

Monday, March 7, 2016

Asterisk and stuff

One of the other fascinations I have is with telephone systems. I have a Cisco 7940, and a 7970 in the house, and I have a Sipgate account for VoIP. It was working fine with one phone, but then I thought I wanted both phones working. SIP is a strange protocol, and is hugely flexible so you can spend happy hours playing with all kinds of things to get it going. The phones are different as well; Cisco rely on having a TFTP server in the network for the phone to boot from, which contains most of the phone configuration. Each phone has a SIP<macaddress>.cnf file in the tftpboot directory that it looks for, to bring up the phone. I had some happy times with Wireshark to find out what was going wrong. Having fixed the 7940, the 7970 uses a similar approach, but a completely different format for the configuration file - now in XML! The phones also have their own web services built in ..

So having the phones working individually, I needed something so I can use them both. There is a lovely bit of Open Source software - Asterisk - that can run on Linux to provide a local PBX solution. So, downloaded that, and it now functions to manage calls coming in and going out on the SIP line.

I then installed Zoiper on all of the mobiles and tablets in the house, and that works well - so I can now call Trish from the office to her mobile, without the call going out over the air - and therefore is free. So far so good.

What I want to do next is to receive incoming calls on the house phone, and send them out to the SIP phones. So, how to solve this?

I did the usual, searched with Google and decided from a ten minute bit of research that the SPA-3000 device, available for pennies from eBay would be a good bet. Ah. Now the real fun begins.

I found the manual online, and there is a very comprehensive Asterisk book for download. I am still struggling though - this is a key part of the home phone strategy, so I can use the existing analogue handsets over DECT to ring them (assuming the phone call is from someone I like - telemarketers will get a very long message advising them that we don't accept unsolicited marketing blah blah on the phone). I will post more as I find out more, but this is a nightmare so far. There are literally hundreds of settings for the SPA-3000.

I may have to sell the little darling and buy a better interface.