User's Manual

APCD-LM043-4.0 13
3 Detailed Description
This section describes the technologies and features used in the LMS4000 900 MHz Radio
Network.
3.1 LMS4000 Overview
Figure 6 is a high-level schematic of the LMS4000 system, showing the key system
components and interfaces.
As shown, each LMS4000 component is associated with one of three major system entities:
• End-user Modem (EUM)
• Communications Access Point (CAP)
• Network Access Point (NAP)
End-user Modem or Customer-premises Equipment
The EUM equipment is installed at the end-user’s premises. It provides an interface to the
customer’s computer or local area network on one side and wireless access to the LMS4000
network on the other.
Communications Access Point (CAP)
The CAP is the collection and distribution point for data travelling to and from the EUMs. In the
EUM-to-network direction, the CAP aggregates the data from the radio channels into a single
data stream, which is passed either directly or over a backhaul facility to the Network Access
Point.
In the Internet-to-EUM direction, the CAP receives data from the Network Access Point and
distributes this data to the appropriate radio channels for transmission to the EUMs over the
900 MHz radio link.