Me R189, User Manual

Page: 97 / 100

- 96 -
12. Appendix
The One-Net encodes the EAS messages per FCC rules for the EAS protocol. The EAS
protocol from the FCC is described as follows (printed directly from the FCC ruling).
The EAS uses a four-part message for an emergency activation of the EAS. The four
parts are; Preamble and EAS Header Codes, audio Attention Signal, message, and,
Preamble and EAS End Of Message Codes.
The Preamble and EAS Codes must use Audio Frequency Shift Keying at a rate of
520.83 bits per second to transmit the codes. Mark frequency is 2083.3 Hz and space
frequency is 1562.5 Hz. Mark and space time must be 1.92 milliseconds. Characters are
ASCII seven bit characters as defined in ANSI X3.4-1977 ending with an eighth null bit
(either 1 or 0) to constitute a full eight-bit byte.
The Attention Signal must be made up of the fundamental frequencies of 853 and 960
Hz. The two tones must be transmitted simultaneously. The Attention Signal must be
transmitted after the EAS header codes.
The message may be audio, video or text.
The ASCII dash and plus symbols are required and may not be used for any other
purpose. Unused characters must be ASCII space characters. FM or TV call signs must
use a slash ASCII character number 47 (/) in lieu of a dash.
The EAS protocol, including any codes, must not be amended, extended or abridged
without FCC authorization. The EAS protocol and message format are specified in the
following representation. Examples are provided in FCC Public Notices.
____________________________________________________________
[PREAMBLE]ZCZC-ORG-EEE-TTTT-JJJHHMM-LLLLLLLL-
(one second pause)
[PREAMBLE]ZCZC-ORG-EEE-TTTT-JJJHHMM-LLLLLLLL-
(one second pause)
[PREAMBLE]ZCZC-ORG-EEE-TTTT-JJJHHMM-LLLLLLLL-
(at least a one second pause)
(transmission of 8 to 25 seconds of Attention Signal)
(transmission of audio, video or text messages)
(at least a one second pause)
[PREAMBLE]NNNN
(one second pause) [PREAMBLE]NNNN
(one second pause) [PREAMBLE]NNNN
(at least one second pause)
____________________________________________________________
[PREAMBLE] This is a consecutive string of bits (sixteen bytes of AB hexadecimal [8
bit byte 10101011]) sent to clear the system, set AGC and set asynchronous decoder
clocking cycles. The preamble must be transmitted before each header and End Of
Message code.