Faxing and PCI (was Re: [Asterisk-Users] Digium cards, so disappointing !)

[Steve Underwood]

Kevin P. Fleming wrote:

>Jeff Gustafson wrote:
>
>  
>
>>	Is there any reason an easier implementation of the same, basic, idea
>>could be created for the "Asterisk generation?"  According to a quick
>>search of H.100 it's "just" a TDM bus.  It handles 2,048 full duplex
>>calls.  Would a lightweight version that only supports 512 or 256 calls
>>be any cheaper?
>>    
>>
>
>It's doubtful. The issues are the cables and connectors are not cheap,
>and getting the boards to pass EMI and other certifications would be
>more complex. In addition, it means every board now has to have support
>for a super-speed TDM bus, even if it's only a 4-port analog interface
>card, and it also needs onboard logic to be able to map channels around.
>That would increase the card cost quite a bit, even for people that have
>no desire to use this method of connection.
>  
>
Rubbish. The 2 buses which preceeded H.100 - SC-BUS and MVIP - *were* 
basically cheaper and simpler versions of H.100. They used ordinary 
cheapo ribbon cable and header connectors, rather than the finer 
geometry cabling used by H.100. The logic needed for them is pretty 
simple - each bus was implemented in a pretty standard and not too 
complex ASIC, which all the vendors used. It didn't cost much to add 
MVIP or SC-BUS to a card, and those buses could handle 512 channels. 
They used multiple 2Mbps E1-like lanes, so they didn't require any super 
high speed operation. Any old TDM bus card - even a 4 channel one - 
should have no problem fitting in with and MVIP world.

Regards,
Steve