In a switch there are 2 ways to get dial tone out of it. Trunk cards and
line cards. Line cards drop out individual POTS lines to a Main
Distribution Frame where they connect to individual pairs and go to your
house/business/etc.
When you order a line side T1, all of the 24 POTS lines are wired into a
D4 bank where each individual POTS line terminates on a corresponding
channel unit. Then it is delivered to you as a T1 facility.
Trunk cards "bundle" individual POTS lines into higher level bitstreams,
ie T1. This is how the PM3 works. It drops out individual channels and
"points" it to a modem.
In Lineside configurations, the channels come out of the switch analog
and are converted to digital by the channel bank. In Trunkside
configurations, the channels stay digital from the switch to you.
-- Kyle Platts Network Engineer !NTERPRISE Networking Services U S WEST Communications - To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message.