Chapter 8 Protocol Decoding    RIGOL 
MSO1000Z/DS1000Z User’s Guide    8-7 
Start Bit: represent when the data starts outputting.  
Data Bits: represent the number of data bits actually contained in each frame of 
data. 
Check Bit: used to check the correctness of the data transmission. 
  Odd Checkout: the total number of “1” in the data bit and check bit is an odd. 
For example, when 0x55 (01010101) is sent, a 1 needs to be filled in the check 
bit to make the number of 1 be an odd.  
  Even Checkout: the total number of “1” in the data bit and check bit is an even. 
For example, when 0x55 (01010101) is sent, a 0 should be filled in the check bit. 
  None: there would not be check bit during the transmission. 
Stop Bit: represent when the data stops outputting. 
 
Press MATH Decode1  Decoder to select “RS232” to open the RS232 
decoding function menu. 
 
1.  Press Decode to turn on or off the decoding function. 
 
2.  TX and RX Channel Setting 
Press Tx to select any channel (CH1-CH4 or D0-D15) as the transmitting 
channel and when “OFF” is selected, no transmitting channel is set. Use the 
same method the set the Rx channel. 
 
3.  Baud Rate Setting 
Press Baud and use   to set the desired baud rate. The range is from 110 to 
20000000. You can also press Preset to select 2400, 4800, 9600, 19200, 38400, 
57600, 115200, 230400, 460800, 9216000, 1M, 2M, 5M, 10M and 20M. The 
default is 9600 and the unit is bps. 
 
4.  Copy Trigger 
Press CopyTrig to copy the protocol trigger settings from the trigger system 
and set the corresponding decoding parameters automatically. During RS232 
decoding, this function is valid only when the trigger type is RS232 trigger. You 
can copy the settings of data channel, width, baud rate, stop bit, check mode 
and polarity. 
 
5.  Polarity Setting 
Press Polarity to select “  (positive)” or “  (negative)” and the 
default is 
. 
 
6.  Order Setting 
Press Order to select “LSB” or “MSB” and the default is “LSB”. 
 
7.  Data Line Setting 
As mentioned before, in RS232, you need to set the start bit, data bits, check bit 
(optional) and stop bit of each frame of data. “Start Bit” is specified by the 
“Polarity Setting”. The setting methods of other parameters are as follows.