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How to use two OBI110 as a Local Area Network Intercom

Started by glfruta, July 24, 2013, 03:26:04 PM

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glfruta

Can someone in this forum post a step-by-step procedure on how to program two OBI110 to act as a local area network intercom without using Obitalk since the local area network doesn't have internet access, just local intranet access.

Explanation of the configuration scenario:

I have a house where I want to connect two OBI110 to communicate two separate rooms. Both rooms have ethernet cables that are connected to the same router in the same subnet, but nothing connected to the WAN port (no internet). Since that router doesn't have internet connection, I cannot connect to the Obitalk servers.

What I woud like to know is if there is some way to set or configure the two OBI110's so I can call from room A to room B and viceverse by pressing a speed dial button to ring the other OBI110 phone or just lift the handset and have the other OBI110 ring the phone in the other room.
I just want to link the two OBI110 to act like an intercom and am not interested in placing phone calls to landlines nor call other phones.

I understand that in order to program the OBI110's I will need to temporarily connect the OBI110's to Obitalk servers to program them, for this I can do so by setting up a test network in my office that has internet access and properly program the OBI110's while connected to the internet. Once both OBI110's are programmed I can disconnect the internet in my office and test to see if both OBi110's can communicate without using Obitalk servers.

I would be very grateful if someone can explain me how to do it please.

azrobert

#1
First, get the IP address of both OBi's.
From a phone attached to the Phone port dial ***1

You don't need to use OBitalk to update the OBi110s.

Attach a computer to the same router.
Type the IP address of the OBi110 into your Browser and hit Enter.

You will be prompted for a UserId and Password.
Both are "admin".


On both OBi110s:

Setup a dummy SIP definition like this:

Service Providers -> ITSP Profile B -> SIP -> ProxyServer : 127.0.0.1
Voice Services -> SP2 Service -> AuthUserName : (any userid)
Voice Services -> SP2 Service -> X_RegisterEnable : (unchecked)
Voice Services -> SP2 Service -> X_ServProvProfile : B

To fix audio problem:
Service Providers -> ITSP Profile B -> SIP ->  X_DiscoverPublicAddress: unchecked

On OBi110#1:
Define speed dial.
User Settings -> Speed Dials -> select any speed dial #, uncheck and set to:
sp2(anything@192.168.1.102:5061)

192.168.1.102 is IP address of OBi110#2

On OBi110#2:
Define speed dial.
User Settings -> Speed Dials -> select any speed dial #, uncheck and set to:
sp2(anything@192.168.1.101:5061)

192.168.1.101 is IP address of OBi110#1

Edit:

When you're finished updating a section, click "Submit" on the bottom of the screen.
When you're finished updating the OBi110, click Reboot on the top of the screen.

Shale

If you want to just pick up the phone and have it dial, search the admin guide for "hotline". I am not going to attempt a step-by-step procedure.

azrobert

#3
For Hotline

On both OBi110s:

Replace Physical Interfaces -> Phone port -> DigitMap:
(<S0:100>)

On OBi110#1:
Replace Physical Interfaces -> Phone port -> OutboundCallRoute:
{100:sp2(anything@192.168.1.102:5061)}

On OBi110#2:
Replace Physical Interfaces -> Phone port -> OutboundCallRoute:
{100:sp2(anything@192.168.1.101:5061)}

The above should call the other OBi110 immediately when the phone is taken off hook.
I tried it on my OBi110 and it took approx 15 seconds before dialing.

Edit:
It's probably a bad idea to replace the DigitMap and Outbound route. It's better to add the above rules.
The DigitMap should look like this: (<S0:100>|...........)
Add the route rules to the beginning of the OutboundCallRoute followed by a comma.
You also need everything in my 1st post except the speed dials.


glfruta

azrobert
I proceeded to set both OBI110's  as described in your step by step instructions.

Tried calling from Phone A to Phone B and viceversa and they worked, but one thing I noticed is that every time I picked up the handset of the receiving phone I had to wait for around 6 seconds before being able to hear the calling phone. The same happens with the calling phone, for when I pick up the handset of the receving phone, the calling phone still has pulsating tone indicating as if the receving phone is still ringing. This tone remains for 6 seconds after I pick the receving handset until full voice communication between the two phones is established, which happens, as I mentioned before, after waiting 6 seconds with the handset in my hands on the receving phone.

Is there any other setting I need to program into the OBI110's so the voice communication is established immediately after I pick up the receving phone ?

Rick

I guess I'm missing something. If you have no internet connection, then the OBi is providing no function - it simply allows you to use your PSTN line, which you could do without it.

If your goal is simply to call room A from room B with an intercom, virtually every wireless phone system on the market allows you to PAGE one handset from another. 

Shale

Quote from: Rick on July 28, 2013, 05:20:58 AM
I guess I'm missing something. If you have no internet connection, then the OBi is providing no function - it simply allows you to use your PSTN line, which you could do without it.

If your goal is simply to call room A from room B with an intercom, virtually every wireless phone system on the market allows you to PAGE one handset from another. 

I think this system is passing the conversations digitally over the LAN rather than over the PSTN line. It may provide more range than a wireless phone, depending on things.

The form factor of a phone may fit some environments better.

azrobert

Quote from: glfruta on July 27, 2013, 09:06:00 PM
one thing I noticed is that every time I picked up the handset of the receiving phone I had to wait for around 6 seconds before being able to hear the calling phone.

I don't know of any parameter on the OBi110 that would cause this behavior.

I have two OBI110s and I can call between them without any delay.

If your router has option SIP ALG, disable it. SIP ALG is known to cause weird problems on the OBI.

If this fails try connecting the OBi110s to the router in your office just to see if it works.

Pinky

Thanks for the great info azrobert....

I'm looking to do something very similar to this with two Obi100s.  Do you know how to configure the Obis to emulate a 2 wire leased line?  While this hotline ringdown configuration is very close to what I want, it's not quite it.  I basically need the OBis to automatically connect to each other without ringing and have it not matter
which side went off hook first.

I'm looking to connect a couple modems through the Obis to provide an IP connection for some legacy devices which require synchronous serial.  While synchronous serial over IP devices do exist, they are quite spendy.

Thank you in advance!


Just for future searching ability, I'd like to add the following so people can find this thread: automatic ringdown line, automatic ring down line, lease line, leased line.

Shale

Quote from: Pinky on July 29, 2013, 03:07:46 AM

I'm looking to connect a couple modems through the Obis to provide an IP connection for some legacy devices which require synchronous serial.  While synchronous serial over IP devices do exist, they are quite spendy.
Presuming the setup conection works, if those are 300 baud, I suspect that would work. I suspect 2400 baud would not work, but I am not sure. I don't have a guess for 1200 baud.

QBZappy

Pinky,

Cool idea of writing tag words in your post in small sized font. I never saw this before. For a moment there I though that you were writing some sort of subliminal message at the bottom. It might be useful for readers who want to tag hard to find threads as well.
Owner of the 1st OBi110/100 units in service in Canada & South America. 1st OBi202 on my street. 1st OBi1032 in Montreal.

Pinky

They are actually 9600 baud modems.  I recently had great success using a pair of VOIP boxes (intended for the two way radio industry) emulating a 4 wire lease line that I connected the 9600 baud modems through.  Ended up being a stable connection, though I think part of the success was the fact it was on a private IP network.  The modems I used for that setup are capable of dialup, 2 wire lease and 4 wire lease.

I was thinking if I could get away with using 2 wire lease line modems, they would be more plentiful and cheap used plus I could use a relatively cheap ATA (compared to the 4 wire VOIP boxes).

Is it too much to ask for out of the OBIs to do 9600 baud even OBI to OBI direct with no VOIP provider?


BTW- QB, I saw the small font technique somewhere else a while back before and thought it useful.

Shale

Quote from: Pinky on July 30, 2013, 01:57:25 AM

Is it too much to ask for out of the OBIs to do 9600 baud even OBI to OBI direct with no VOIP provider?
Actually I don't know. I have never tried anything like that. I am probably over-pessimistic. I hope your ethernet path is low on jitter.

ianobi

The general advice for faxing over voip is to lower speeds to 9600 Baud and ensure that only uncompressed codecs are used such as G711. OBi devices do use G711U and G711A codecs, so that side should be ok. You would probably have to go peer to peer, not via a voip provider, to ensure that signals don't get compressed by the voip provider.

I believe that there are some differences between how faxes and straight modems work, but you need someone more expert than me to talk about that! All I know is they both push data down telephone lines.

If your two modems can seize a telephone line and auto-answer when they receive ringing, then the above azrobert config should work. You might need to experiment with the config to eliminate connection delays. Also note, that the original question concerned two OBi devices on the same subnet. If you try this project out, then it would be easiest to set it up on the same subnet first for easy fault finding.

Anyhow, looks like an interesting project. We would all like to hear about it if you give it a try - we might even help   :)

Pinky

Sounds good Ian and Shale-
I've got a couple more modems on the way to play with on the bench so I'll give it a shot.  I've got two OBIs already so I'll try out this configuration and see what's what.

I understand about the jitter- I was concerned about this with my 4 wire VOIP box setup.  That particular install is on a low latency private IP network which has a very consistent 10ms ping .  Knowing the buffer time of the boxes, the modems, and the ping, the total latency of the synchronous serial data is about 125ms.

Is there a buffer adjustment on the OBI I can set?

ianobi

QuoteIs there a buffer adjustment on the OBI I can set?

Not that I know of. I'm guessing that OBi design is simply optimised for the codecs it uses. Pure data was never a consideration.

I have never really understood this setting:

Service Providers > ITSP Profile A > RTP > DSCPMark

It has something to do with DiffServ, which has something to do with QoS. It's default value is 46. Any DiffServ experts out there?

QBZappy

Owner of the 1st OBi110/100 units in service in Canada & South America. 1st OBi202 on my street. 1st OBi1032 in Montreal.

ianobi

Wow! I drifted into this thread looking for beer and pizza and ended up with homework  :D

Pinky

Guess what?  The modems work on the OBIs!  Two identical modems on OBi-100s

9600 baud totally stable.  I have not used the automatic ringdown config outlined above but I tried it using the direct OBItalk numbers as well as my DID PSTN #s on voip.ms.  The modem training sequence takes about 20 seconds but it locks on and stays.  I've left them connected overnight and all day on direct mode and they're totally solid.

I think the long training is due to the fat jitter buffer in the OBI.  The modem test indicates about 450-500ms delay- and that's when they are going direct to each other on the same switch.

It would be great to see Obihai make the jitter buffer length setable in the next firmware release.  Seems like that should not be too big a deal considering all the other variables you can set in these bad boys.  The Obi seems like an extraordinarily well thought out piece that delivers for very little money.

I think my next step is to get them registering with an Asterisk server and let the server do the interconnection.

ianobi

That's interesting. Using OBiTALK the default codec would be G711U for both legs of the call so uncompressed all the way. G711U and G711A are widely used by most voip providers, so looks like your idea is workable for dial-up end to end modems at 9600 baud or lower.


QuoteWow! I drifted into this thread looking for beer and pizza and ended up with homework   :D

Well I did my homework, so kindly provided by QBZappy. I now understand why the default for this is 46:

Service Providers > ITSP Profile A > RTP > DSCPMark: 46

46 is the best setting for voip. I now don't understand why the setting is configurable, but I'm not going to do any more homework on this issue   :)