COMPSEC FFASTEST PROTOCOL & JFT PROGRAM
               FOR USE WITH SATELLITE PHONES

Comspec Digital Products, Inc. is a manufacturer of hardware and software for the transmission of data on the asynchronous and synchronous International dial network,Cell Phone, ISDN, V-Sats, and Inmarsat HSD & ASD Systems. COMSPEC focuses on the Inmarsat “A & B” High Speed Data (HSD) service, both simplex and duplex. COMSPEC developed special software and hardware to:
      *   Allow the IBM compatible PC to move large data files to and from a remote Inmarsat Terminal to another Inmarsat Terminal
                         or
      *   To a headquarters’ office location

     Two synchronous HSD systems are available:
      *    One for the DeskTop PC called ffastestsPC-HSD, a short slot AT-ISA buss board.
      *     One for the LapTopPC called ffastests PCMCIA, a Type 2 PCMCIA card.

The Windows 3.1X, 95, 98, NT or MS-DOS software systems can function like a simple electronic mail gateway to the other Unix, Mac, Windows, or DOS networks using the on demand dialup Switched 56 kbps, dedicated V-Sat, or ISDN 56, 64,  & 128 kbps International Networks. The system is an easy to use turnkey package with built-in diagnostics and a very error tolerant transmission protocol which can re-link and resume from a sender power fail or complete link disconnect. The only thing the end user needs to do is setup methods (scripts, links, icons, or batch files) for moving his data into and out of our mailboxes (Subdirectories/Folders) precompressed and ready for transmission.

The “ffastest protocol” is a proprietary protocol written in very tight code to maintain the maximum data throughput, in the presence of multiple satellite delays with high errors, and to give the user a minimum Inmarsat bill for large data file transfers. This software is not a warmed over implementation of the TCP/IP, SDLC, or HDLC protocols. The code is very demanding on the PC’s processor and the interrupts. We are now delivering a Windows 95, 98, 3.1X and DOS versions of the software. A Windows NT version shipped fourth quarter of 1999. The Windows & DOS Inmarsat throughputs, when transmitting precompressed files, of 350,000 & 410,000 bytes ((8 bits per byte) per minute at 56 & 64 kbps are typical.

The Comspec DPI software only asynchronous package Just File Transfer (JFT) is designed for use with “off the shelf” async modems with speeds from 2.4 to 33.6 kbps and with the ISDN terminal adapters which support V.120 and Bonding async protocols at 64 and 128 kbps. JFT is ready to use with Inmarsat M, B, and Mini-M Terminals and with the Iridium and AMSC satellite terminals with setup scripts for the direct data modes of those terminals. JFT does not need any of the modem’s internal error correction and it will transmit data with 100% packet errors on the line. If you need to send data on expensive and error prone circuits, such as: HF, VHF, UHF, and Cellular radio; Third World and some other International telephone links; Inmarsat satellite land mobile or marine, then it is costing you a lot of money not to use “JFT.” The JFT system has a resume function that will recover and resume sending a file from a sender disconnect or a complete power fail. JFT will never send the same file twice. The current shipping “32 Bit API” software has long folder and file name support and a new ”Browse” functions to make it easier for the user in selecting files and folders to send. JFT will run on the Inmarsat HSD service at 28.87 kbps isosynchronous or will operate behind our DT-101 multiplexer at ll5.2 kbps and transmit a compressed one million-byte file in 3 minutes and 40 seconds. The DT-101 multiplexer is a voice/data multiplexer from MultiTech modified for use on the Inmarsat HSD system. The DT-101 “Data Talker” will provide a 115.2 kbps asynchronous link that looks like a “Buffered null modem cable” with a 850 millisecond satellite delay, when used on the Inmarsat HSD service. The DT-101 can be used to allow high-speed data connections for any asynchronous software package such as “CC-Mail, Note, MS-Mail, PC Anywhere, LAN access, and Internet access.”  The DT-101 has one voice line and the DT-102 has two.

              Spectrum Services International
                    Manassas, Virginia, USA
         Phone (703) 369-4997  Fax: (703) 369-9382
                 E-mail: info@satellitecom.org