[Asterisk-Users] Analogical FXO vs. BRI dialing speed

[Steve Underwood]

Steven Critchfield wrote:

>On Mon, 2004-02-16 at 07:39, Jean-Marc V. Liotier wrote:
>  
>
>>When dialing out, will a call be established significantly faster by an
>>ISDN adapter such as an Eicon Diva server compared to an analogical FXO
>>such as Digium's X100P ?
>>    
>>
>
>Analog, nothing logical there.
>
>ISDN will be faster dialing out as you will communicate with asterisk
>via the dialpad where you want to be connected too, and if you are on a
>analog line, asterisk will repeat the digits to the telco switch in
>analog just like you did but at a specific cadence. Since a DTMF digit
>is around 450 to 800 msec, and in that time frame you can transfer all
>  
>
Eh? A DTMF digit is about 100ms - roughly 50ms on and 50ms off. Your 
overall conclusion is right though. Digital is much faster. On a PRI T1 
some managers complain they only get 23 channels, while they would get 
24 if the used robbed bit lines. However, for lines carrying lots of 
short calls the faster call setup on a PRI means it is usually a 
significant win overall.

>the call setup information digitally, the call could be setup in the
>equivalent of a single digits time, let alone the next 6-10 digits.
>
>Incoming, the calls are again signaled digitally and acknowledged with
>the switch in less time than it takes to make the first half of a ring.
>On analog you will want to wait till the second or third ring to get the
>CallerID, but it was there to start with on the ISDN call.
>
>On my PRI line, calls are answered and prompts played without a single
>ring event being heard by the caller.
>  
>
This can be a little confusing for the caller, but thankfully it also 
screws up a lot of telemarketer systems. Dialogic et al don't recognise 
the phone as properly answered if they never hear the ringback tone :-)

Regards,
Steve