Firmware for the P650R-T1 v3 ADSL router, hardware version 3. The 201512 in the name likely indicates a December 2015 build, although that is not certain. The 1004 KB RAR is sized for a full router image intended for recovery or update. Match the hardware version on the label before flashing, because v3 firmware is specific to that revision. Upload is usually done through the web interface, or through TFTP and a serial console when the modem no longer starts normally.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @afsbiosfree. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →