[EMAIL PROTECTED] 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 _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
