The SPB firmware has two operation modes: “N-mode” and “SX-mode.” 
Applicable personal computer loader varies  depending on the firmware used. 

<N-mode> 
The SPB is set to N-mode at the factory shipment (default). Programs of N-mode are compatible with those of FLEX-PC N series, our old PLC. 

<SX-mode> 
Programs of SX-mode are downward compatible with those of MICREX-SX series SPH, our current PLC. 
You can change the operation mode of the SPB firmware to SX-mode by using the “System software utility” included  with the personal computer loader. 

* V**.10 or later version of SPB supports SX-mode. SPB earlier than V**.10 is fixed to N-mode. 
* For more information on "N-mode" and "SX-mode" in the SPB series, refer to the following How-to Guide. 
   How-to Guide "Introduction to Necessary Devices for SPB (SPE) Programming" (GE0303)