[asterisk-users] Seeking advice about ISDN BRI Cards

Lukasz Sokol el.es.cr at gmail.com
Thu May 28 08:07:23 CDT 2015

On 28/05/15 10:18, jg wrote:
>> Thank you all for valuable input,
>> another question: when do I actually need the echo cancellation 
>> (hardware / on board /on module ) ?
> It depends on your environment. If there are still analog devices in
> addition to VoIP, I'd say always, but Asterisk has a rudimentary echo
> canceller already on board. The Telcos use echo cancellers
> themselves, but it cannot hurt to have a hardware canceller on your
> BRI card.

I am going to have to be more specific, I see...

We have the ISDN lines incoming into little boxes on the wall (BT ISDN 2e) 
from where they are plugged into existing ISDN PBX. The ISDN2e boxes have 2 ports,
but 1 of each are connected to the ISDN PBX.

There is nothing else connected to the ISDN2e boxes, no phones connect to these
lines 'directly'.

> Nowadays I see more problems with reverberation in connection with
> cheap speakerphones or simple mics and speakers on PCs, but that's a
> different story.
> jh


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