User's Manual

Table Of Contents
Page 1–31
18 September 2007
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
eNfusion™ HSD-128 High-speed Data Terminal
Figure 1–7. Reduced Functionality Dual-Channel System
(6) ISDN Circuit-Switched Data Interface
HSD and HSD-X transceivers connect to a variety of interface options. The physical
interface for ISDN service is EURO S/T, which supports several types of connections
to user equipment.
HSD and HSD-X transceivers provide either one or two ISDN S/T bus interfaces
(depending on the number of channel cards and mode of installation of the unit).
Each bus is capable of hosting up to eight, EURO ISDN physical devices—which
means a one-channel system supports up to eight physical connections to EURO
ISDN devices; a two-channel system supports up to sixteen physical connections to
EURO ISDN devices.
Each channel card supports communications with one, 64 kbps, ISDN B channel on
an ISDN U interface bus. If the channel(s) is “busy” or “in-call", the request for service
is denied (the system is busy).
For ISDN data devices that support bonding with a two-channel card HSD transceiver,
the device uses both ISDN B channels to increase data throughput as long as no
other devices are “in call.”
For incoming calls, each channel card (ISDN BUS) is assigned a Forward ID. The
Forward ID is assigned Inmarsat Mobile Numbers (IMNs) for each service type. Each
service type has an associated Multiple Subscriber Number (MSN). The MSNs are
configured in the ISDN devices to direct incoming calls of different service types to
the appropriate device.
For a two-channel HSD transceiver, two IMNs are assigned for each service type.
"System Operation" on page 2-1 provides examples and a detailed description of the
routing assignments for the HSD transceiver.
Several ISDN interface options are shown in Figure 1–8. The physical interface is
EURO S/T, which can support up to eight simultaneous connections to user
equipment. In the illustrated example, the ISDN port is only used for circuit-switched
services (Swift64 Mobile ISDN).
Data I/O Processor
ARINC Connector
HSD Transceiver
ISDN S/T ISDN S/T
RS-232
RS-232
10BT
Laptop computer
Serial or
USB
Channel Card
Channel Card
ISDN S/T
RS-232
Terminal Adapter
ISDN S/T