H | ELECTRICITY |
04 | ELECTRIC COMMUNICATION TECHNIQUE |
L | TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION |
1 | Arrangements for detecting or preventing errors in the information received |
12 | by using return channel |
16 | in which the return channel carries supervisory signals, e.g. repetition request signals |
18 | Automatic repetition systems, e.g. van Duuren system ; ; ARQ protocols |
1829 | Arrangements specific to the receiver end |
1854 | Scheduling and prioritising arrangements |