EMS Technologies Canada Ltd. A781 User Manual

23-15-30

 •

Classic Aero-H+—Provides packet data services at 600 bps, 1200 bps, or 10500 bps 
over the PRT channel combination and half-rate circuit switched voice or data service 
over the C channel.

 •

Swift 64—Provides packet switched Mobile Packet Data Service (MPDS).

 •

SwiftBroadband—Provides AMBE+2 voice (circuit-switched) and broadband packet 
switched services. The equipment can achieve aggregate rates of 432 kbps, but data 
rates may vary with network load.

The ARINC 781 SATCOM Avionics System consists of the Satellite Data Unit (SDU), the 
Satellite Data Unit Configuration Module (SCM), and optionally, the Flange Mount Power 
Amplifier (FMPA). 

Figure 1-2 illustrates the ARINC 781 avionics system.

The SDU is the central communications processing and control unit and largely 
determines the functionality of the complete SATCOM system. It manages interfaces, 
routing and priorities, and call channel establishment and tear down. When configured 
without an FMPA, the SDU provides RF power amplification using an internal high power 
amplifier (HPA).

The SDU is divided into several Shop Replaceable Units (SRUs) that are electrically 
connected via the backplane. Various SRUs are also connected using RF cables. 

The SCM is an external peripheral of the SDU and provides a dedicated interface to the 
SDU. It stores Secure and User ORTs (Owner Requirement Tables) and a Swift 64 
Forward ID. The SCM can accommodate up to four Universal Subscriber Identity Modules 
(USIM) that store subscriber information for the SBB network.