Phones to Asterisk

I want to connect with Asterisk more than 30 analog phones.
Have You heard about any hardware that support this ?
This will be PBX with 30-100 phones simultaneously.
I am think about something what is called channel bank.
Is it a good idea ?
I know that I can find 24xFXS card, but this is to small.

Thank You for quick answer.

There are a few ways of doing this.

You can get two TDM2400 cards in the same box I think, although this is not usually recommended.

A channel bank is a T1-POTS interface device- it has up to 24 analog ports (FXO or FXS) and connects to * via a T1 (PRI) interface. You can easily double up on these- get a 2-port or 4-port PRI interface card and more channel banks.

There are also a few other ways to do it

You can get a gadget called a voice gateway- it’s like a channel bank except it uplinks to * by SIP (over Ethernet) instead of of via a PRI. This has a few advantages, namely the echo cancellation and encoding are handled by the gateway, freeing the * box CPU to do other things. It also can grow more, you generally shouldn’t put more than 4xPRI per server (96 channels per box), whereas you can have many 100’s of SIP clients.

There is also a novel approach from a company called Xorcom- they have a USB channel bank. Same as a normal channel bank and supports a lot of ports, but links via USB2.0. You can put more than one per server.

Lastly, it will cost more $/port but you should consider IP phones. IP phones have feature buttons (transfer/conference/etc) which analog phones don’t (you need flashing and star codes and stuff).

Good luck!

I think about Sangoma card A200 ( it is very flexible with echo cancelation ).
Why is it not usually recommended in one box ?
I want connect Telco line using E1 span ( also Sangoma card 4xE1 ).

I think about channel bank, but I have to find prices for this stuff. Maybe You know something about ?
Does Asterisk work with usb channel bank ?
I want to have up to 100 phones simultaneously.
I have many analog phones ( why change it ). When the features will not be efficient I will develop CTI application, which brings more features.
A count of PCI slots is very big problem, because it is not scalable solution.
I am wondering if buying hardware pbx is not a better solution. Then I will integrate this pbx with asterisk ( small callcenter system ).
I have many offices to arm with this kind of solution.


I would look at a couple of vegastream 48 port SIP gateways and an E1 card in the system.

This will give you some resiliancy as well

sangoma is fine to stack, because they work via a backplane connector (each 5 sangoma cards, if configured right, only have 1 pci slot and connect to each other via a backplane). This is fine. It can be bad to use too many digium tdm cards as they each generate a lot of interrupt traffic…

I am considering AstriBank-32, but I do not know how does it work.
It is a good idea to use usb ( pci are free ). Problem with Sangoma and
24xFXS -> we can use that way only one pci.
Lots of interrupt is very serious problem and now I am thinking about
hardware which manage to coupe with 2xE1 ( Telco lines ) and 3x32 FXS
without SIP.
I do not trust SIP implemented in Asterisk for many users - I do not know how does it works ( 100 users ).

I think it will work far better than trying to get 3 usb connected devices working. or 4 24 port tdm cards.

Asterisk SIP isnt perfect but it isnt THAT BAD. Besides with the voice gateway as I understand it the gateway becomes one SIP peer, so you dial like SIP/gateway/25 for port 25.

when i speak of many interrupts i mean when you have 3-4 or more digium cards… sangoma wont have that issue but you will run out of slots in your chassis. You could get two TDM2400’s i suppose (i think) but it’s not exactly elegant.

USB should work fine as long as your usb chipset doesnt completely suck. I’ve only read one or two reviews of the astribank but from what i read it seemed like a good product.