Hi,
Serial port is used to connect e1/t1 link to the router port.
A type of interfce could be v.35 or g.703. For v.35
typical setup as mux--g.703 modem--dsllink----v.35 modem---v.35port of router.
It will give you 2mb unframed output for e1
for g.703 the setup is mux---g.703modem---g.703modem--g.703 router interface
If distance is less there you can exclude g.703 modem pair from in between. ABove is example of synchronous connection
Asynchronous is something like dialing through modem to central site through public telephone network.
You can also call it as dial on demand..typical example is dial-up, isdn
hope this helps
Regards
Mahesh
