7 replies to this topic

[ThoughtPhreaker]

So earlier this month, I bought a TDM410P off of eBay for the sake of poking around with Asterisk a little more. Holy hell, is it noisy! Now to be fair, this is kind of a shady clone instead of the real deal ($85 for a fully loaded clone or $600+ for the real thing from Digium. It was worth a try, right?), but my experience with ATAs in general has been pretty bad.

So I've been wondering, what's the cheapest way to get good analog?

A while back, I remember seeing some guy documenting the process of getting an Avaya and Nortel PBX working in his house. If you've got a half hour to kill, they're good reads -

http://wildflower.di...nityathome.html
http://wildflower.di...rtelathome.html

But anyway, I started searching for used Avaya parts, and they're actually pretty cheap. $40 for a used analog line card that supports 16 extensions, and from my experience, they sound pretty much as good as a POTS line. Overall, a whole PBX is about $300, $350 or so. I've always wanted a real PBX, so I'm thinking this and a T1 card could be the answer to getting good, cheap(er) analog.

So how about you? Have you found a good way to do cheap analog extensions?

[systems_glitch]

I'd say give a real Digium card a go. I've got a real TDM400 series card and the analog quality is excellent. I've also got two Digium IAXy devices (the S100 and S101, the former uses a standard FXS module)...quality is better with the TDM400 card. The IAXy devices are satisfactory though, and will even handle fax and modem signals. One of mine is being used as a remote extension in another building across fiber with a pair of 10baseFL tranceivers.

IIRC, the TDM4xx series is the same base PCI card, just with different prepopulated FXS and/or FXO modules. I'd highly recommend looking for a real Digium device. I picked mine up with three FXS modules and one FXO module for around $75 shipped. They're not officially supported by Digium and they are PCI, so not too desirable for production systems using new hardware. Great for hacking though!

This guy has a bunch of genuine TDM400 cards with 2x FXO and 1x FXS:

http://www.ebay.com/...=item35be5bb5b5

EDIT: They're not officially supported /anymore/; that is, they're past EOL.

Edited by systems_glitch, 19 July 2012 - 06:39 PM.

[Y0ungBra1n]

Correct me if I'm wrong as I'm just getting into the whole VoIP scene but I think I read somewhere that you could hook up an SPA3102 to the analog line and configure it as a trunk in asterisk. Wouldn't that be one of the cheapest ways to get a custom PBX in house? Those ATAs are only like 50 or 60 bucks and asterisk can be installed on any old machine.

Does that even make sense?

Edited by youngbrain, 20 July 2012 - 01:08 AM.

[systems_glitch]

I don't know much about the Cisco ATAs -- I've always stuck to Digium stuff when it comes to real hardware that will have to interact with copper line and Asterisk. If the goal is just to play with Asterisk for cheap, then the guys at http://www.ipkall.com/ will give you a free DID in Washington state, and you can use a softphone to play around (there's a really decent softphone for Android, cSimpleSip, and some OK ones for iOS).

It looks like that Cisco ATA will act as both kinds of ATA -- copper to SIP and SIP to copper (FXS and FXO in the same box). Not particularly cheap though, especially not if its performance is like the majority of SIP ATAs I've played with. Plus, if ThoughtPhreaker has a box with a free PCI slot and wants to play with an older Digium board, the results will be generally better.

Also with the "cheap ATAs," you can use some WinModems with Asterisk as a FXO card. I forget which brands Digium used, but they will more or less work. I've heard the quality is pretty low with most of the WinModems, but I've never tried it myself.

Don't forget that you can use the sound card in your Asterisk box as the operator's device from the console!

[ThoughtPhreaker]

Thanks for your advice . I may have to end up giving a real 400P a go.

Maybe I should clarify a bit - the whole idea isn't so much to do VoIP as it is to use Asterisk as a test bed for a few things on copper. And to the 410P clone's credit, the FXO modules on it did work pretty well. I would like to stick a few analog extensions on there, though, and a spare PCI slot isn't a problem.

One thing I will say about Winmodems is I believe Andrew has a few he's using with Motorola chipsets. As far as I can tell, they seem to work reasonable well so long as they're capable of spitting out uLaw or 14-bit PCM. Some only support Vox ADPCM or 8-bit linear formats. I've heard something about low volume, but his didn't seem to have that issue. Then again, he might've been doing something with the line impedance too.

As for DIDs, I'm not really in a position to be doing VoIP right now. ipcomms.net used to give out free DIDs, but only does it for 30 days now. I think I have a grandfathered free account if you want me to point a DID your way. The email address and everything on the account is changeable, so it's yours if you want it.

[systems_glitch]

As for DIDs, I'm not really in a position to be doing VoIP right now. ipcomms.net used to give out free DIDs, but only does it for 30 days now. I think I have a grandfathered free account if you want me to point a DID your way. The email address and everything on the account is changeable, so it's yours if you want it.

Thanks for the offer, but I'll leave it to someone else -- I've got a DID through did4sale, which gives me 20 inbound channels. I use it for work/home phone, so it's one of those covered expenses that also allows me to play with Asterisk.

Asterisk + Digium card does work well for a copper testbed. I'm thinking about picking up another TDM400 series card and throwing together a temporary switch to share our one office line while management figures out what they want to do for a permanent phone solution. The office is wired with Cat3 from an existing client, and everything terminates in a nice 66 punchdown in the server closet...ripe for the VoIP hacking!

[phreeman]

If I was to spend any money over 100 on a card, it would be a sangoma. I understand that digium changed their chipset a couple of years back, however I have never had any issues with the sangoma cards. Their quality is really well made. a200

I used to have issues with the rhino drivers (at first) and echoes on the digium cards etc but never an issue with an a200 with hec. just my 50 cents //peace

[Andre van dem Helge]

Actually I have had pretty good luck with the PCI modems lately. I know first time I tried them there was terrible echo, especially the first few seconds.

Maybe I learned how to use it, maybe the drivers were improved. Point is I've installed these and used them trying to go 100% VoIP at some locations, but still keeping a backup just in case. Route the calls so if the VoIP (inbound) doesn't go through it connects through the phone line. Super saver tip: AT&T you can order a residential line or DSL at a business location, lower cost no contracts.

I've got a box full if you want one.