User's Manual

Page 1–40
18 September 2007
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
eNfusion™ HSD-128 High-speed Data Terminal
(c) Multi-Channel Configurations
The HSD Multi-Channel configuration combines a dual-channel, Stand-Alone
Mode HSD-128 Transceiver with one or more single-channel HSD-X
transceivers to add additional channels to the system.
Each channel provides an ISDN 64 kbps connection that can be used for voice
or data services. The two channels in the HSD can be internally bonded to
provide a 128 kbps ISDN data connection. Externally, all four channels shown
in
Figure 1–10 can be combined to provide a single 256 kbps capability with the
help of a router, Ethernet hub, or Terminal Adapter.
The HSD-128 is the master of the system, and as its name suggests, it controls
the overall operation of the Multi-Channel HSD configuration. It keeps track of
time and allocated power and may command the HSD-X “slaves” to terminate
calls under certain conditions, such as an ocean region change. The HSD-X
transceivers are wired to the HSD-128 HPA and therefore compete equally for
HPA power allocation.
The transmit signal of each channel is fed through a combiners/attenuator
combination to the HPA located in the HSD and ultimately to the antenna.
Conversely, the receive signal from the antenna goes through a series of splitters
on its way to each channel.
On power-up, HSD-X transceivers go through an initialization process that
identifies and communicates the number of extension channels and their position
in the system chain back to the HSD-128 controller.
The block diagram in Figure 1–10 illustrates the system function of the HSD-128,
two HSD-Xs, and the antenna system.
Figure 1–10. Multi-Channel System Block Diagram
HSD-128 (Master)
HSD-X
(Slave)
HSD-X
(Slave)
? \
HGA
D/LNA
ACU
\
ISDN
Transmit Path
Receive Path
Crosstalk Bus
ISDN
MPDS (RS232)
Ethernet (10Base T)
(Optional)
ISDN
ISDN
MPDS (RS232)
MPDS (RS232)
Ethernet (10Base T)
Ethernet (10Base T)