[Asterisk-Users] DS3000P - 20 E1 capacity on single card

[Jon Bebeau]

Gee...If I were the betting type, I'd take a few that there's going to be 
some flavor MVIP connector on that card.

----- Original Message ----- 
From: <tmassey at obscorp.com>
To: "Asterisk Users Mailing List - Non-Commercial Discussion" 
<asterisk-users at lists.digium.com>
Sent: Tuesday, April 12, 2005 2:20 PM
Subject: Re: [Asterisk-Users] DS3000P - 20 E1 capacity on single card


> asterisk-users-bounces at lists.digium.com wrote on 04/12/2005 10:51:49 AM:
>
>> Andrew Kohlsmith wrote:
>>
>> > secondary card for DSP functions is very inefficient of the PCI
>> bus.  I'd be
>> > curious to know if the Digium cards can even do PCI-PCI DMA.
>>
>> The Digium TDM cards can DMA into any RAM accessible over the PCI bus,
>> regardless of whether it is located on the motherboard or on a PCI card.
>
> That's not the point.  The point is that you have to transfer voice data
> twice:  once from the DS3 card to the co-processor, and once from there to
> the eventual destination (probably system RAM).  If the co-processor is
> integrated into the DS3 card that first transfer is handled and
> echo-cancelling is performed *before* the data hits the PCI bus.
>
> In other words, a PCI-based co-processor would double the PCI bus
> bandwidth necessary.  And with a latency-sensitive product like voice, bus
> contention is not something you want to add to!  :)
>
> Tim Massey
>
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