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ZP9D-115RM-LR Radio Modem
40
RN (Delay Slots) Command
<Networking & Security> The RN
command is used to set/read the
time delay that the transmitting RF
module inserts before attempting
to resend a packet. If the
transmitting module fails to receive
an acknowledgement after sending
a packet, it inserts a random
number of delay slots (ranging
from 0 to (RN minus 1)) before
attempting to resend the packet.
Each delay slot is 5 msec (when
BR=1) and 54 msec (when BR=0).
If two modules attempt to transmit at the same time, the random time delay after packet
failure allows only one module to transmit the packet successfully; while the other module
waits until the channel available for RF transmission.
RN Command is only applicable if retries have been enabled [RR (Retries) Command] or if
forced delays will be inserted into a transmission [TT (Streaming Limit) Command].
RO (Packetization Timeout)
Command
<Serial Interfacing> The RO
command is used to set/read the
Packetization Timeout setting. RF
transmission begins when data is in
the DI buffer and either of the
following criteria are met:
• RO character times of silence on
the UART receive lines (after
receiving at least 1 byte)
• RB characters have been received
by the UART
RB and RO criteria only apply to the first packet of a multi-packet transmission. If data
remains in the DI Buffer (UART receive) after the first packet, transmissions will continue in
a streaming manner until there is no data left in the DI Buffer.
When RO is the transmission-beginning criteria
: The actual time between the reception
of the last character from the UART and the beginning of RF transmission will be at least
800 µsec longer than the actual RO time to allow for transmission setup. Additionally, it is
subject to 100-200 µsec of additional uncertainty, which could be significant for small
values of RO at high UART bit rates.
The correct UART character time (10, 11, or 12 bits) is calculated based on the following
criteria:
• 1 start bit
• 8 data bits
• 0 or 1 parity bit [as determined by the NB (Parity) Command)
• 1 or 2 stop bits [as determined by SB (Stop Bits) Command]
AT Command: ATRN
Binary Command: 0x19 (25 decimal)
Parameter Range: 0 - 0xFF [38 ms slots]
Default Parameter Value: 0 (no delay slots inserted)
Number of Bytes Returned: 1
Related Commands: RR (Retries), TT (Streaming
Limit)
AT Command: ATRO
Binary Command: 0x21 (33 decimal)
Parameter Range: 0 - 0xFFFF [ x UART
character times ]
Default Parameter Value: 3
Number of Bytes Returned: 2
Related Commands: RB (Packetization
Threshold)