I know that when ATT delivers a circuit it's signaling is usually b8zs/esf. Can the same be said for Verizon and other carriers that they use the same.
Thanks in advance!
When I worked with the carriers (AT&T, Sprint, Winstar, Teligent etc.) circuits were normally installed as B8ZS/ESF because they allowed a full 64K per DS0. An AMI/SF circuit only gave you 56k on a DS0.
We would usually install an AMI circuit to older PBXs and then there was always an "are you sure? phone call that went out.
BUT - if I wanted an ESF circuit - I'd make sure I specified it.
Sam
Moderen day T1’s are all almost exclusively ESF/B8ZS so defaulting to that would be the safe call for any LEC BUT framing and coding are set to how the circuit was ordered… It should be specified by the customer/end-user when ordered.
I still run into D4/AMI but it is in installation where the T1's have been there for years (5+). I haven't ran into any new circuits were D4/AMI was required (and a few were it wasn't offered).
Plus B8ZS/ESF works better. Always seemed to have strange call progress issues with D4/AMI.