pl. clarify the following:
1. under what situations do we use NM-30DM
2. i have to connect 30 branch offices to one central office. Each branch will have a small router with dial-up port & dial-up modem. At central location i propose to take Channelised E1 module and a E1 link to PSTN.
does this situation call for Digital modems (NM-30DM)