Ewave Radio Modem User’s Manual V1.02
Copyright © 2001 by Ewave, Inc.
15
4.6
TX POWER ON/OFF
Send:
Tn
Transmitter Power On.
Tf
Transmitter Power Off. Radio Modem can still receive incoming radio
packets while Tx Power is Off.
4.7
RETRY ON/OFF
Send:
Rn
Retry/Ack. On; The modem will automatically re-send the data packet until
it is acknowledged by the other modem. If new data is sent to the modem
before the current data packet has been acknowledged, the retry-attempt is
aborted and the new data is processed.
Rf
Retry/Ack. Off; Each data packet is transmitted exactly once.
4.8
SET CHANNEL
Send:
Cx, where x is [0x31-0x58]
Sets the current channel to (x – 0x30.)
While the modem is capable of using 40 channels, only 5 channels are available to the user in the standard
modems:
Channel # (1-40)
Channel #
(in hex.)
Channel Command
Channel Char.
in Decimal
Channel Char. in
Hex
4
0x04
C4
52
0x34
13
0x0D
C=
61
0x3D
22
0x16
CF
70
0x46
31
0x1F
CO (“See-letter-Oh”)
79
0x4F
40
0x28
CX
88
0x58
Both modems must be on the same channel to communicate.
4.9
SET PACKET SIZE THRESHOLD
Send:
Px, where x is [0x31-0x58]
Set the size threshold for data packets. How this parameter is interpreted
depends on the modem’s protocol configuration.
For “RM2000”-configured modems, (which uses fixed-length data packets), this parameter sets the length
of the data packets. In this case, x is 48 + the desired fixed-length packet size. Example: For a fixed-
length packet size of 20 bytes, x would be 48 + 20 = 68, which in ASCII is “D”. Therefore the command
“PD” will set the fixed-length packet size to 20 bytes.
For “Checksum”- or “Break”-configured modem’s, (which send variable-sized data packets), this
parameter sets the maximum length – once this length is reached (or the Wait Time is exceeded) the packet
is transmitted. In this case, x is interpreted as a Boolean-mask as follows:
