Digi M10 - Manual (Page 8)

Digi m10 Technical Overview
Digi International, Inc. © 2009 Page 8 of 26
1. General Description
This chapter provides an overview of the Digi m10 Satellite Modem and its features.
1.1 Background
The ORBCOMM system is a two-way system that supports communication to and from mobile or
fixed satellite modems, also called Subscriber Communicators (SCs) . In most applications, a
message or other data is first generated by an SC. From that source, the message is transmitted
to the nearest ORBCOMM satellite. The satellite downlinks the message to the Gateway Earth
Station (GES) , which then transmits the message to the desired Gateway Control Center (GCC) .
Within the GCC, the message is processed and forwarded to its ultimate destination by the
Gateway Message Switching System (GMSS) . The destination may be another satellite modem,
a pager, a corporate resource management system or any personal or business e-mail or Internet
address.
The ORBCOMM system is available to transfer information for an end user whenever a satellite is
in view of the SC. If the satellite is connected to a GES, the satellite is considered in real-time
messaging mode, and the message is passed immediately through to the GCC for routing to its
final destination. If the satellite is not connected to a GES, the satellite switches to a store-and-
forward mode to accept Global Grams . Global Grams are short messages (up to approximately
200 bytes) stored on-board the satellite until it connects to the SC’s host GCC through an
affiliated GES.
For detailed information on the ORBCOMM system, refer to the ORBCOMM System Overview
document that was provided as part of your Digi JumpStart Kit..