Edoardo Sabadelli (v3.0) - personal web playground

Grandstream HT 503, PBX, SIP: my recipe for VoIP

Sat, 16 May 2009 12:47:50 GMT

As some of you may know, I live about 2,037 km far from my family in Italy and since I moved to Oslo I always had some problems communicating with some people in my family.
The main reasons are that they are not computer literate (like my mom), they don't have a (decent) internet connection (like my sister) or simply they are not that often online (again like my sister).

So, what did I do to solve the problem?

Scenario

At my parents' home in Italy there is an ADSL flat internet connection, and a PBX which currently serves 3 standard telephones around the house.

At home here in Oslo I have a cable flat internet connection provided by Get and no telephone lines.

The solution

My idea was simple, use an interface between the PBX and the internet, so that I could use my pc and VoIP to call it and interact with the PBX.
This interface is commonly known as ATA and it's easy to find such devices for home use at a reasonable price.
The advantage of having a PBX is clear; the ATA just becomes another telephone connected to the PBX and can behave exactly like them.
In other words it can call the other phones and receive calls from them, plus can dial external numbers.

Grandstream HT 503

I spent quite some time researching, annoying my buddies on the Perl.it IRC channel and reading manuals to understand what I really needed and if a particular ATA was suitable for what I wanted to do.
All the phone terminology was new to me, but soon I understood that I needed an ATA with an FXO port for connecting it to the PBX.

The Grandstream HT 503 seemed to be the right device for me, with one FXS and one FXO port with separate SIP accounts, and so I bought one and spent quite a lot of time during my one-week Easter vacation in Italy trying to make it work... and I succeeded!

The configuration

I'm not going through all the details, but basically the whole system configuration required work both on the PBX, on the ATA and a stupid setting in the router.
If you want to know more feel free to contact me.

Router

This was actually the reason why at first I wasn't able to get the ATA work.
Since the SIP protocol uses several UDP/TCP ports for authenticate and transmit the audio packets, the router must have UPnP enabled.

ATA

I disabled the FXS port, since I don't have attached any analogic telephone to it, I only use the FXO, configured with a SIP account and the following relevant settings:

PSTN Ring Thru FXS: no, which avoid calls to the ATA pass thru the FXS port before being forwarded to the FXO

Number Of Rings: 1, which minimizes the time needed for an incoming call to be bridged to VoIP

Unconditional Call Forward to VoIP, which automatically forwards every incoming call to the ATA to the SIP account I've configured in my softphone

PIN for PSTN calls, which should avoid unauthorized uses of the PBX and the phone line

DTMF via RFC2833, which allows me to dial password and numbers using tones with the keypad of my softphone

Register expiration: 30 minutes, I lowered the threshold after experiencing some problems of ATA offline

PBX

On the PBX I changed the settings for the ATA internal number so that it does not ring when an external call comes in.
Normally all the internal telephones ring, but remember that I configured the automatic forward to VoIP and I don't want my SIP account to ring every time someone calls my parents.

Softphone

I currently use Gizmo, a free multi platform SIP phone software.
The only setting here was for the DTMF tones to use out-of-band RFC 2833.

In other words

What I can do now is:

1) call an internal phone at my parents' house:
From my softphone I call the SIP number of the ATA, when it picks up I hear a tone and I dial the password, if correct I hear the PBX tone and I can dial the number associated to any internal phone and talk with my parents :)

2) call an external number:
After calling the SIP number of the ATA and accessing the password protected PBX line, I can access the external line, then dial any number and let my parents pay :P

3) receive a call:
My mum can pick up any telephone at home and dial the internal number associated to the ATA, which after 1 ring forwards the call to my SIP account and if I'm connected I receive the call through the softphone.

4) receive a call from outside my parents' house:
Someone calls my parents' phone number and talk with them, then at some point my parents can forward the call to me simply dialing the internal number associated to the ATA and I can also forward the call back to any telephone at home,

But...

You may ask: why didn't you just pay some service like SkypeOut and call every number you want in Italy?

The answer is: well, because of several reasons.
First of all, why should I pay for calling my mother when I can do it for free (free as in we both pay already for internet connection)?
Second, Skype uses a closed proprietary protocol, which for people like me doesn't sound all that right.
Third (optional), because that way is too simple, where is the fun? ;)

Happy VoIPing! :)

A TV set for the Macbook

Sat, 07 Feb 2009 00:52:15 GMT

It's been since I moved to my flat in Oslo that I have cable TV (provided by Get), but without a TV it wasn't that exciting :P

So, long story short, I bought an Elgato EyeTV Hybrid device with Elgato EyeTV 3 software bundled in the package.

It's a USB TV tuner that has an analogic TV tuner, a digital tuner for DVB-T, and a digital converter for DVB-C also.

The thing I needed most was the DVB-C support, and not many devices have it.

I'm really happy with this little new toy, the quality in digital on the cable is great, the analog channels are not so bad after all, as for the terrestrial digital (DVB-T) I tried with the antenna included in the package, the quality of course depends on the position of the antenna and the strenght and quality of the signal, so sometimes you can experience signal interruptions, but the quality is good also.

I'm looking forward to test DVB-T in South Africa and Italy; here in Norway you can find those channels also on the cable (both digital and analog).

Of course just installing the software and enjoy the shows was too simple :)
I wanted an EPG for the channels available on the cable.

Some digital channels broadcast already their EPG, but some others and all the analogic ones not.

In the Channels section of the EyeTV application, it's possible to set how to get the EPG for every channel; one of the options is xmltv.

XMLTV is a XML format for describing TV listings, and there are some resources around updated daily.

After some researching I found this for Norway: http://mspc.no/xmltv/ which keeps a file with the guide for each channel for 30 days.

So I just needed a way to make something useful out of all those files.

xmltv is an open source project for managing TV listings from several countries in XMLTV format.

It turned out that is actually written in Perl and uses several CPAN modules and some scripts.
There is a collection of grabbers for different countries and the one for Norway uses the sources from
http://mspc.no/xmltv/ for building a single EPG file with all the configured channels.

So, how to load this EPG into EyeTV?

That was tricky to find out, no way to load the data from EyeTV, so Google pointed me to this article: http://benblaughs.blogspot.com/2008/03/using-xmltv-feeds-with-eyetv.html.
Looking at the script I found out how it can be done: just load the file when you run the EyeTV application.
From the command line type:
open -a EyeTV.app my_epg_listing.xml
and presto! the EPG are available :)

God Jul!

Thu, 18 Dec 2008 23:21:06 GMT

Tomorrow will be the last day of work before the Christmas vacation I'll spend in Italy with my family as always.

It's been a long time since I last saw some of my relatives, almost half a year, so I'm looking forward to spend some time with them again and Christmas is always one of the best moments for a family to get together, and after Christmas my girlfriend will come to Italy as well.

There is a lot of snow on the mountains now in Italy, even too much, so we might decide to spend a day on the snow, maybe skiing...

Anyway it'll be a nice vacation, a needed break from the work and the "usual" life, to spend with family and friends.

I'm leaving Oslo soon, but this year I did some Christmas decorations at my place...
I wanted to do things in big, and so I thought "Why don't put lights on the big crane standing in front of my window for some months?".

So I did :P

God Jul to all! :)

FreeBSD clock problem

Mon, 10 Nov 2008 19:47:49 GMT

A few days after I installed FreeBSD 7.1 BETA, with lots of help from ferz on my old and trustworthy laptop, I noticed a problem with the clock.

The time was running too fast!

I was debugging something in cron because it wasn't executed, and while having a look at the time in top, I noticed that the seconds were incremented the double at each refresh.

I asked around, then I remembered gq was working with some BSD distros, so I sent him an e-mail explaining my problem, and in a few hours it was fixed! :)

These were the steps:

1) run sysctl and find out the relevant information about the kernel clock source:
> sysctl -a | grep kern.timecounter.choice

My output is:
kern.timecounter.choice: TSC(800) ACPI-safe(850) i8254(0) dummy(-1000000)

2) try to change the value of kern.timecounter.hardware using the ones listed by the previous command, with
> sysctl kern.timecounter.hardware=[new value]
(ie. > sysctl kern.timecounter.hardware=i8254) and check if the clock works correctly after that.
If yes, good, problem solved :)
If no try with the other possible values.

What worked for me was i8254.

3) read some relevant information and learn how to make the changes permanent.

4) profit!

Many thanks to ferz and gq for all the help!

Andy McKee and Don Ross in Göteborg

Sun, 05 Oct 2008 14:03:27 GMT

I discovered Andy McKee on youtube some months back and I was impressed by what he can do with a guitar, it's basically fingerpicking but with a lot of tapping and percussion on the strings and on the guitar.
He also plays with unusual tunings and uses the capo in creative ways.

Definitely another world!

Since I'm learning some of his songs I wanted to catch the opportunity to see him live in Göteborg, so last Friday with Margaux we went to see the concert where Andy played together with Don Ross.

The concert was amazing, very good sound and venue.

They played both solos and songs in duo.
Don is definitely a frontman, funny and entertaining, while Andy seemed more shy; both are amazing guitarists!

The concert hall was quite small, so we weren't that far from the stage after all and I manage to take some quite good pictures using a "new" tele I got recently from my father (gq do you remember?).

I posted the best pictures on Flickr.

After the concert I met both and now I'm the proud owner of a signed copy of their CD "The Thing That Came From Somewhere".

I had a great time and both are now in my list of favourite musicians.

Norway tour 2008 (the story)

Sun, 07 Sep 2008 00:52:40 GMT

Of course I didn't write anything during the tour.
I must say I'm definitely not a blogger, I hope at least to be better in taking pictures and videos and make something nice with them.

In this trip I discovered an interest in video also, but maybe it's just yet another thing I'd like to spend a lot of time that I don't have on ;)

Anyway, at least a brief summary of the tour would be nice, so here it is.

July, 4th

Friday, after work we collected all our stuff from our places and literally filled Peter's Fiat Punto.

The first part of the itinerary was from Oslo to Stavanger driving through Telemark where we slept in a camping Friday night.

July, 5th

On Saturday, on the way to Stavanger, we had a stop and climbed the famous Prekestolen aka Pulpit Rock, an amazing cliff 604 metres above the sea.
Late in the evening we reached our second camping site, where we spent 2 nights in a cabin.

July, 6th

Sunday, dedicated to Stavanger, unexpectedly nice city, with a beautiful area full of white and coloured wooden old houses.
We also visited the very interesting Norsk oljemuseum, about the history of oil, gas and the petroleum industry in Norway.
We also spent a lot of time taking pictures of jellyfishes in the harbour.

July, 7th

On Monday we left Stavanger and drove to Bergen.
During this trip we saw some of the most amazing waterfalls of the whole tour, and of course we took tons of pictures and videos.
We arrived in the evening and met a friend of Luca, had a walk and drunk a beer in a nice old pub with some live folk music.
We spent the night in a room kindly offered by a couple of hungarian friends of Peter.

July, 8th

Tuesday was entirely dedicated to Bergen, one of the most famous cities of Norway, well known for the rainy weather.
Of course for us was different, we brought the sun and a clear blue sky :)
The city is great, especially the old parts and the famous Bryggen, the old buildings in front of the fjord.
That day there was a big italian Costa Crociere cruise, and I heard a lot of italian.
I ate some awesome salmon and scampi bought in the fish market.
Later we took the funicolar that goes to Fløyen, from where there is a spectacular view of the city and the fjord.

July, 9th

On Wednesday we travelled to Geiranger, another famous touristic destination in Norway, known for the beauty of the fjord where it's located, with majestic mountains and waterfalls.
We arrived late in the evening, just in time to go up to a viewpoint and take some pictures of the fjord and the small town before go to sleep in a nice dependance of an hotel.

July, 10th

Thursday, we drove back to the mountains behind Geiranger from which you can have an amazing view of the valley and the fjord.
Then we took a ferry towards Ålesund; the most expensive of the whole trip, but the waterfalls are unique and I think there isn't another way to cross the fjord and continue to Ålesund where we arrived in the evening.
Before reaching the camping site where we spent the night, we went up to a hill from where you can see the whole city and the open ocean, and had a walk in this nice city.

July, 11th

On Friday we drove from Ålesund to Trondheim.
On the way we stopped in Trollstigen, another attraction with huge mountains and a steep road with many hairpins.
In the second part of the journey to Trondheim we had some rain, which wasn't a problem anyway, since we stayed in a cabin.

July, 12th

Saturday we spent the whole day visiting Trondheim, still some rain that luckily didn't ruined much.
It's a nice city, with an old part as many others we visited.
In the evening we went back to the cabin and grilled pølse on the shore.
The trip was almost over, this was the last day before going back to Oslo.

July, 13th

Sunday we drove the whole rainy day back to Oslo.
I was pretty tired and I slept a lot, but after a week of sun, fjords and the best of Norway, I didn't miss much during this day.

The trip was just amazing, one of the best so far together with the one in Svalbard.

I plan to make a dvd of this tour, with some parts of the videos also.

For now I made a small slideshow with a selection of the best landscape pictures I took during the tour.
The video is available on youtube.

And here, enjoy! :)

Norway tour 2008

Thu, 10 Jul 2008 00:06:40 GMT

It's been more than a year since I first moved to Norway now, and I can't say I've seen much in Norway.
I've been most of the time in Oslo, and did just a few trips outside.

A tour around Norway, for an expat that lives there, is something mandatory, so, together with Luca and Peter, we planned an on the road trip.

The initial idea was to drive up to North Cape, but in a week or so would have been too much, so we reconsidered the itinerary to include at least the most common destinations up to Trondheim.

3 guys, 1 Fiat Punto, 3 DSLR kits, 3 sleeping bags, a tent, a lot of luggage and food... on Friday evening we packed the car and started the Norway tour 2008 :)

I won't have many occasions to post during the trip, since we will be often in campings or other places without internet connection, but I'll write something daily and post at the first occasion.

Stay tuned!

Home sweet home

Sun, 08 Jun 2008 10:16:29 GMT

Next Wednesday I'll go back home to Italy for a 2 weeks vacation, meeting family, old and new friends, hopefully enjoing them as much as possible.

6 months for me is a long period, I can't wait to see my family, my sister, how much my nephew is growth, and my grandma who is 88 years old and starts getting older and loosing some shape.

People often feel the need to escape from the family to find their way, but when you are far away from the ones who care about you, you realize how much they are important and how much they have contributed to build you the way you are... and you start thinking you should do more for them.

Now that I'm experiencing this, from the big boy I was, I feel I'm a little man, with many questions and little answers.

I will spend some days alone also, I planned a 3 days trip, myself, my beloved motorbike, roads, mountains, nature...
I really hope the weather won't ruin the trip, since is a thing I thought about many times and never did.
Now the right moment has come, for many reasons.
I'm confident it will help me finding some answers and inspiration...

"Life's a journey, not a destination..." so what's next?

Spring... or summer?!

Wed, 07 May 2008 21:37:00 GMT

In the past weeks the weather was great, sunny and warm; and now the days are becoming longer and longer, we already have light from 5 to 21:30!

Anyway, it's been a long time since my last post, many things happened and now it's time to write something...

First of all I'm blogging from my new MacBook, I bought it in Italy when I was there for Christmas.
I'm quite happy about it, no big issues for now.

Recently I bought a bycicle also and now it's a pleasure run along the river in the morning while commuting to work.
When it's time to go back home it's another story, but I'm quite satisfied with my performances (24 gears help though).

This week, or the next one, I'm going to buy a second hand Pentax K10D DSLR from Peter and finally stop waste money to buy films and develop ugly photos... a new era will arise :)

Next 17-18 May I'll skip the norwegian national day and spend the weekend in London instead with 3 other italians, it will be fun and hopefully I'll have the occasion to train a bit with the reflex.

Hmm... looks like I'm spending lots of money lately! \o/

I would like to write some more specific posts about this things, so stay tuned!

Sky art

Mon, 11 Feb 2008 20:24:07 GMT

A few weeks ago I saw the first spectacular sky phenomenon since I'm here in Norway.

No, it's not an aurora borealis but something else equally stunning and beautiful.

The norwegian word for them is perlemorskyer: polar stratospheric clouds aka nacreous clouds.
It seems that these phenomena are quite rare, so I consider myself lucky to have seen them live!

I wasn't prepared for them, so I didn't take nice pictures, but at least these photos have the particularity to have been taken in daylight, and not during twilight as most of the great photos you can see in Flickr.

Take a look also to this amazing photos my colleague Claudio took in those days and shared with the mankind!

Now I'm looking forward to see the midnight sun next August when I will travel far north to Svalbard for a short trip!