Murata Electronics North America 910M Manual Do Utilizador

3.1.  Packet Formats 
 
The byte formats for each packet type are shown in the table below.  Packet fields are 
organized to fall on byte boundaries.  In the case of bit-level fields, most-significant bits 
are on the left. 
 

MRTP 

(WIT910)

 packet types (

modes 01-02

): 

 

Transmit and Receive: 

Base

 DATA

 

 

 

1110 1001

       

00HH HHHH   LLLL LLLL   

<0-208 bytes data> 

Remote 

DATA  

1110 1001   0000 0000   LLLL LLLL   

<0-212 bytes data>

 

 
 
 Receive 

only: 

 

CONNECT 

1110 1001   10HH HHHH   RRRR TTTT   00NN NNNN   

<3 byte remote 

ID>  

 

 

DISCONNECT 

1110 1001   11HH HHHH   0111 1111    

 

 

 

 

H

 

:  handle number (0-63) 

 

 

L

  

:  data length (0-208 for base, 0-212 for remote) 

 

 

N

 

:  remote's previous network number (if roamed) 

 

 

R

 

:  receive sequence number (from previous cell) 

 

 

T

 

:  transmit sequence number (from previous cell) 

Note that while the packet length can be set to 212, the maximum number of bytes 
transmitted per hop is limited to the lesser of 212 or the length specified by maximum data 
length. Packets with a data length longer than that will be discarded and not sent. See Get 
Maximum Data Length for more details. 

 
 
3.1.1.  Data Packet   
 

Modes 01 & 02:

   

Base

 

1110 1001   00HH HHHH   LLLL LLLL   

<0-208 bytes data> 

 

 

Remote  1110 1001   0000 0000   LLLL LLLL   

<0-212 bytes data>

 

 
This packet carries user data.  The handle number is the handle of the receiving remote. 
When data is being sent from a remote to the base, no handle number is required. Up to 
212 bytes (208 for base radios) of user data may be carried per data packet but no more 
than is specified by the maximum data length parameter. The radio will not break up a 
packet over multiple hops. Packets with a data length greater than maximum data length 
will not be sent and will be discarded. This parameter is variable and depends on the 
number of remotes currently registered.  
Handle 63 is reserved for broadcast packets from the base to all remotes.  
Acknowledgment requests are not supported for broadcasts.  For this reason, it is a good 
idea to send broadcast messages several times to increase the odds of reaching all 
remotes. 

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