Wavecom W61PC V7.5.0 - Manual (Page 137)

WAVECOM Decoder W61PC/LAN Manual V7.5 Transmission Modes  127
Parameter Value
Frequency range HF
Operation modes Duplex ARQ TDM
Modulation FSK
Symbol rate 96.0 Bd
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
Additional Info Cyrillic third shift with parity
CIS-14 employs a radio channel Symbol rate of 96 Baud.
Synchronizing to a CIS-14 signal may be initiated by selecting a baud rate or Auto. Starting Auto will au-
tomatically determine shift, center frequency and baud rate.
The two first bits of the multiplex frame identify the channel state as IDLE or TRAFFIC. Then two bit inter-
leaved M2 data code words follow. The last two bits are parity bits used for error detection. Parity is calcu-
lated depending on the position of ‘1’ bits.
In Code Check the simple data format of CIS-14 with only two parity bits may unfortunately lead to una-
voidable detection errors.
CIS-36
CIS-36 in error-correcting traffic mode is using a horizontal line- and vertical block-error-detection. Each
block has ten data frames and a parity frame. Each data frame has five data characters and one parity
character. In case an error is detected the receiving station starts ask for a frame repetition (NAK instead
of ACK) from the last complete and correctly received frame.
Parameter Value
Frequency range HF
Operation modes Duplex ARQ
Modulation MFSK-36
Speed 25, 50 or 100 ms
Receiver settings DATA, CW, LSB or USB
Input format(s) AF, IF
CIS-36 is operating with Symbol rates of 10, 20 or 40 Bd which is equivalent to tone duration of 100, 50
or 25 ms.
Transmissions in CIS-36 are mostly in Russian using an ITA-2 alphabet. CIS-36 is a full-duplex mode with
two transmission frequencies, but can also be used in simplex mode.
CIS-36 is based on the older PICCOLO-MK1 system. However, the signal is not symmetric and uses three
frequency groups with 10, 11 and 11 frequencies. The tone spacing is 40 Hz. The theoretical bandwidth is
1400Hz.
In on-line crypto traffic mode the control tones #1, #12, # 24 and #36 are rarely sent so between the
three frequency groups a spacing of 80 Hz seems to appear.
The decoder shows the shift cursors at the tone position #2 and #35 (resulting in a 1320 Hz shift).
The 10 Bd variant is used for manually transmitted operator messages and is mostly unencrypted. The au-
tomatic switching of the tone length is initialized by control sequences.
When message traffic has to be sent, the system switches to 20 or 40 Bd. This part is either coded or
online encrypted in almost every transmission. Special control sequences are used for transmission con-
trol, call set up and clearance.
CIS-36 also has SELCAL and link establishment features.