User's Manual Part 1

18 APCD-LM043-8.0 (DRAFT C)
3: Detailed Description
3.1.2 Communications Access Point (CAP)
The CAP is the collection and distribution point for data travelling to and from EUMs. In the
EUM-to-network direction, the CAP aggregates 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.
Key Components
The following key components of the Communication Access Point are described in detail on
the following pages:
• CCU on page 18
• Cavity Filters on page 20
• Lightning Arrestors on page 20
• Transmission Line on page 20
• Antenna on page 20
• Ethernet Port on page 20
CCU
The CCU, shown in Figure 9, is the wireless access point for up to 300 end-user modems. The
functional blocks of the CCU are illustrated in Figure 10.
Figure 9 CCU