On Sat, 26 Jul 1997, Dan Swartzendruber wrote:
> At 11:52 PM 7/25/97 -0500, you wrote:
> >
> >AMI is not a good choice for a data circuit, and I'm not sure the PM3 even
> >supports it. It has been some time since I was around the details of
> >this, but as I remember it, AMI does not have enough line transitions to
> >allow proper clock recovery. Unless the line is very busy (to keep
> >transitions high) you will get errors on the link. B8ZS forces a high
> >enough line transitions rate through enforced bipolar violations to allow
> >decent clock recovery, and should always be used on a data circuit.
>
> This is incorrect. B8ZS will get you the maximum 1.544 mb/s data rate,
> but AMI is perfectly usable (how on Earth do you think people used T1
> circuits before B8ZS was available?) Using AMI, you can set each DS0 to
> be 56K instead of 64K. This gives you an aggregate 1.3 (approx) mb/s
> data rate, with the proper one-bit density. Any decent T1 CSU/DSU will
> allow you to configure this.