[Asterisk-Users] T1-PRI deployment questions...

[Charles E. Youse]

On 29 May 2003, Steven Critchfield wrote:

> On Thu, 2003-05-29 at 10:44, Charles E. Youse wrote:
> > B8ZS is required for PRI.  It's a digital service and can not handle the
> > loss of data required for AMI.
>
> I wasn't aware that AMI lost data. AMI just inverts polarity on the line
> for every other 1. B8ZS does the same thing but intentionally introduces
> errors on the line to maintain 1's density. Neither one is lossy.
>

AMI is lossy.  When the ones density in the signal is too low, AMI
will insert ones to ensure that the far end does not lose sync.

C.