[Asterisk-Users] USB channel bank?

[Rob Scott]

In what way is USB unreliable?
Is USB in general unreliable?
(I haven't used it much except for my mouse and the USB floppy.)
Or is it workstation/server chipsets?
Is it the handset adapter?
Is it the zaptel drivers?

Potentially it could be a lot cheaper than many of the other solutions
offered.
If these things costs $50 per port (I would expect a lot less in bulk as
they have only one or two small cheap chips on them) then a 10 channel
offering would be in the $500-600 dollars range or so. You'd need a
case, maybe an internal hub and probably some power.
If you need more channels then plug another box of 10 into another USB
port.

The problem I see with the PCI cards is that they are either cheap low
density and you run out of PCI slots quickly, or they are high density
and you run out of money quickly.

-----Original Message-----
From: asterisk-users-admin at lists.digium.com
[mailto:asterisk-users-admin at lists.digium.com] On Behalf Of Steven
Critchfield
Sent: 19 February 2003 18:06
To: asterisk-users at lists.digium.com
Subject: Re: [Asterisk-Users] USB channel bank?


On Wed, 2003-02-19 at 09:19, Rob Scott wrote:
> I was just thinking that connecting to handsets seems to be a major 
> shortcoming at the moment. You can purchase an expensive channel bank 
> and a card to drive it or not much else.
>  
> Is it possible to make an asterisk system that will connect to say 16 
> handsets using using 16 USB adaptors? Would it work with the current 
> software setup? Would USB be good enough for it?
> (Maths tells me that 16 * 64k = 1 Mbps which a single USB channel
> should be able to handle, but is it true?)
>  
> Ultimately, would it not be possible to make a USB channel bank? Plug 
> it into an Asterisk server?

>From experience, USB is not a stable interface. At 16 channels you will
have enough users to make it rough to work through instability. The more
ideal solution would be to fund Marks development of drop and insert
functionality, then make a PC that boots from flash and creates a TDMoE
link to a machine and drop and inserts channels to the station cards. 

Greg said that the estimated price of the 4 port FXS card was going to
be $305. I'd love to see them come up with a 8 port version as well.
Maybe use the 2 lines per jack trick that Rhetorix does on their FXO
cards. 

You could probably get the total cost of a TDMoE to FXS machine down to
less than the cost of a new channel bank.

$150 new case,MB,cpu,ram, on board ethernet, and video
$305 4 port card
$305 4 port card
$120 320mb flash card
$20  IDE to flash adapter
-----------
~$900 for 8 ports on the end of a ethernet cord.

Thats about what I spent for my system at home, $289 on ebay for channel
bank, and $500 for T100P card. Granted the ebay find was lucky. Most
Channel banks worth having don't go for that low.
-- 
Steven Critchfield  <critch at basesys.com>

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