[Asterisk-Users] Codecs and bandwidth

[Brian Capouch]

Tim Pushor wrote:
> Hi Friends,
> 
> Something I'd like to shed some light on if possible - how is it that a 
> single ISDN conversation only uses 64K for bidirectional communication 
> (using ulaw, correct?), but on several occasions now have seen 
> references to ulaw voip conversations using 64K per side of the 
> conversation, plus packet overhead 

ISDN, like T1, is full duplex.  So your 64K channel is 64K in each 
direction, up and down.

B.