[asterisk-users] FXS channel banks

[Faraz Khan]

I would however be interested in knowing how these USB channel banks  
work out in a extremely large environment. Cost/Reliability and  
management wise.Keep in mind that grandstream now has a 24 port FXS  
gateway which retails for $700- and their newer 8 port gateways are  
extremely good.


Quoting Steve Totaro <stotaro at totarotechnologies.com>:

> On Fri, Mar 7, 2008 at 8:02 PM, Tzafrir Cohen  
> <tzafrir.cohen at xorcom.com> wrote:
>> On Fri, Mar 07, 2008 at 03:00:03PM -0500, Jay R. Ashworth wrote:
>>  > On Fri, Mar 07, 2008 at 02:14:57AM +0200, Tzafrir Cohen wrote:
>>  > > >     
>> http://www.voipon.co.uk/xorcom-astribank32-32-fxs-channel-bank-p-530.html
>>  > > >
>>  > > > Trouble is, you'll need 7 32-port units to cover your needs  
>> and I'm not
>>  > > > sure if USB2 is up to driving that many ... Tzafrir?
>>  > >
>>  > > One USB connector can take a number close to that easily. But even if
>>  > > USB were the bottleneck, you would just add another USB controller in
>>  > > the form of PCI card and get extra bandwidth.
>>  >
>>  > Is there any reason you'd want to do that on a system of that scale
>>  > instead of just using Ethernetted FXS boxes on a dedicated 100Base?
>>  >
>>  > Even if you didn't want to use reinvite, seems you'd still win just
>>  > from the less expensive host interface (I can't understand people using
>>  > T-1 interfaces for FXS channels either, honestly, in the current
>>  > environment).
>>
>>  USB is very cheap. It's in every computer. A dedicated ethernet segment
>>  costs more to set up that an extra USB segment (a 10$ for an extra USB
>>  controller? 20$ for a USB hub? a bit more for the wiring?).
>>
>>  TDMoE is more complicated as the latency is higher and the jitter is
>>  larger.
>>
>>
>>  Now both thing have been (T1 channel banks, and TDMoE) have been done by
>>  others. People do use and buy them. I don't intend to say that they
>>  don't. But ours does as well :-)
>>
>>
>>  --
>>                Tzafrir Cohen
>>  icq#16849755              jabber:tzafrir.cohen at xorcom.com
>>  +972-50-7952406           mailto:tzafrir.cohen at xorcom.com
>>  http://www.xorcom.com  iax:guest at local.xorcom.com/tzafrir
>>
>
> Ethernet/SIP is going to be by far the most flexible.
>
> You can have much longer cable runs without some kind of USB repeater
> device.  Switches are cheap, CAT5/6 is cheap.
>
> You could put a Quintum Tenor AX 48 Port (for instance) in one section
> of a building, campus, LAN (WAN if you are daring) and the server
> could be anywhere, not tied by 15 or 30 foot USB cables.  Then if you
> are doing new wiring, you can run the shortest distance from the
> location of the SIP FXS device to the phones.
>
> You can have redundant, self healing links as well as link aggregation.
>
> I cannot see how TDMoE or USB come anywhere close to this flexibility
> and certainly don't see it being a fit for high port densities like
> discussed.
>
> I see TDM0E as something that a tech guy thought would be cool (and it
> is but not very practical) and a USB device something suited for the
> SoHo (but missing the scalability, redundancy, and flexibility that IP
> gives.)
>
> Thanks,
> Steve Totaro
>
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-- 
Faraz R Khan
Chief Architect
Emergen Consulting Pvt Ltd
www.emergen.biz