The ORBCOMM System is a wide area, packet switched, two-way data communication system. Communications to and from Subscriber Communicators (SC) to ORBCOMM Gateways are accomplished through a constellation of Low-Earth Orbit (LEO) Microstar satellites. ORBCOMM Gateways are connected to dial-up circuits, private dedicated lines or the Internet.

The ORBCOMM System consists of a Network Control Center (NCC) that manages the overall system worldwide and three operational segments:

Ø a space segment consisting of 36 LEO Satellites.

Ø a ground segment consisting of Gateway Earth Stations (GES) and control centers located throughout the world.

Ø a subscriber segment consisting of communicators used by ORBCOMM System subscribers to transmit and receive information to and from the LEO Satellites.

RF communication within the ORBCOMM System operates in the very high frequency (VHF) portion of the frequency spectrum between 137 and 150 (MHz). The ORBCOMM Satellites have a subscriber transmitter that provides a continuous 4800 bps stream of packet data. Each Satellite also has multiple subscriber receivers that receive short bursts from the SCs at 2400 bps. The ORBCOMM System will be capable of providing near real-time wireless data communications service around the world.

All communications within the ORBCOMM System must pass through an ORBCOMM Gateway. An ORBCOMM Gateway consists of one Gateway Control Center (GCC)—the facility that houses the computer hardware and software that manages and monitors message traffic—and a GES. The GES provides the link between the Satellite constellation and an ORBCOMM GCC.

Using the ORBCOMM System, a typical messaging scenario will proceed, as shown in the following sequence:

Ø An ORBCOMM System subscriber creates a message, which is intended for receipt by another subscriber’s home computer. Using an e-mail program on a laptop PC, the subscriber downloads the message to a SC.

Ø The SC transmits the message to the Satellite that receives, reformats and relays the message to a GES.

Ø The GES transmits the message over a dedicated line to the GCC that places the message on the public switched network for delivery to the receiver subscriber’s PC Internet provider.

Ø The receiver subscriber downloads the message once the computer makes a connection via modem to its Internet service provider.

Ø A message from the home base to the subscriber follows the reverse route: PC to the Internet over a public switched network to the GCC, GCC to GES, GES to Satellite, and finally Satellite to SC and SC to the user display. Even “direct” subscriber-to-subscriber transmissions must pass through an ORBCOMM Gateway.

The software is able to decode the continuous 4800 bps stream of packet data coming from a satellite. Not all messages could be shown as text, but all messages are available in hexadecimal notation.