9
10 – TEST CODE GENERATING PROCEDURE
1) Set the CW/RTTY selector to RTTY.
2) Set the MODE button to the desired mode.
3) Press the GEN button. The audio monitor will give a transmission sound and, at the same time,
a test code will be provided at the KEY OUT terminal.
4) The speed can be changed by pressing the SPEED button.
5) In TOR mode, ARQ or FEC is selected by pressing the USOS/AUTO switch.
6) Press the GEN button again to stop the test code generation.
11 – TOR
The CWR-880 is equipped with TOR mode decoder function which is not widely known. Here the
outline of the TOR mode and the operating procedure will be explained.
TOR is a communication system in conformity with the CCIR recommendation 476-2 which was
adopted in the second general meeting of CCIR in 1970 for the purpose of improving the maritime
communication, comprising two fundamental communication modes, ARQ (Automatic Request for
Repetition) and FEC (Forward Error Correction).
ARQ (Automatic Request for Repetition)
ARQ is used mainly in individual communication between a coast station an a ship station. In ARQ
mode, if an error is detected in the received characters, request for retransmission is sent auto-
matically until the correct character is received, ensuring virtually error-free transmission. In this
mode, however, only one receiving station is allowed, rendering the communication privacy. (But
the CWR-880 is capable of decoding the communication between two stations by means of a spe-
cial method.)
FEC (Forward Error Correction)
FEC is a one-way error correction system of time diversity feature which transmits the same char-
acter twice. An erroneous character which cannot be corrected is shown by a space. This system is
suited to the transmission of a same message to a number of stations, such as broadcast transmis-
sion.
Amateur radio station
(Since AMTOR for amateur stations conforms to international standard, an amateur station can re-
ceive with international TOR system.)
3.5 MHz band:
Around 3.574 MHz, around 3.630 MHz
7 MHz band:
7.075 MHz – 7.095 MHz
10 MHz band:
Around 10.145 MHz
14 MHz band:
14.070 MHz – 14.080 MHz
21 MHz band:
Around 21.075 MHz
28 MHz band:
Around 28.705 MHz
