[Asterisk-Users] ZtDummy vs Hardware

[Kristian Kielhofner]

Jean-Michel Hiver wrote:

> I was wondering what could be pros and cons of ztdummy vs proper timer 
> device (i.e. X100P).
> 
> I am going to set up an asterisk server in europe (to do trunking, to 
> save bandwith) and I was wondering if it'll be OK to  get it going with 
> ztdummy.
> 
> Furthermore, I have only a 1024/256kbps PPPOE DSL link and I need to 
> squeeze 12 channels through, I was wondering which codec would be 
> suitable for this? Is g.729a going to be indispensable or can I get away 
> with something like GSM?
> 
> Cheers,
> Jean-Michel.

Jean-Michel,

	Ztdummy can be okay, but true hardware timing WILL be better.  But, as 
Rich pointed out, that 256kbps ADSL is probably going to hurt:

256 - 41 = 215kbps usable bandwidth (%16 PPPoE overhead)

IAX2 trunking with g729: 40kbps

each add. call: - 10kbps

So, 215 - 40 - 110 = 65kbps

You only have about 65kbps to spare, and all of this is based on ideal 
(theoritical) conditions.  I doubt that those 12 calls will sound okay, 
or even work at all...

But, you can always try!

--
Kristian Kielhofner