Table of Contents
Advertisement
7. HSD COMMUNICATIONS
7.6
Usage Hints
Applications
HSD communications can be used for
Network connection via TCP/IP router
Sending digital images
Sending large files
Teleconferencing
Voice coding
Communication with other makes of Inmarsat-B terminals
For communication over a network, HSD communications time may increase
depending on communications content. In this case, normal telephone and fax
communications are disabled (except distress), thus frequency of
communications and communications time must be carefully considered when
drawing up communications plans. If communications overlap one another, it may
be necessary to install an additional MES.
Landline
Most landlines use ISDN circuits, and rules of operation vary with country. Thus
several ISDN terminals may be necessary.
Circuit delay
Most landlines uses ISDN circuits. Since the rules and regulations for ISDN vary
with country use the appropriate ISDN terminal.
Propagation delay
A delay of 240 msec exists on the satellite circuit line between the MES and coast
earth station. A 100 msec delay occurs in Tx processing and Rx. Furthermore, a
propagation delay may occur on the landline between the land terminal and coast
earth station depending on the distance between them.
Line delay
A delay of about 15-20 seconds occurs on transmission of file from an HSD
Terminal to coast earth station.
7-10
Advertisement
Table of Contents
