After a main firmware upgrade, your IP phones (DT300/DT700 series) may show "Protocol Mismatch." You must separately update the VoIP DSP chip. Download the DSP_SL1000_Vx.xx.srec file and load it via PCPro under "VoIP Resource Manager."
The NEC SL1000 has gone through several major firmware epochs. Knowing your current version (displayed via the PCPro programming tool or by dialing a display phone feature code) is step one. nec sl1000 firmware download
: The browser-based alternative for system maintenance and updates. Update Methods After a main firmware upgrade, your IP phones