Reset by software - use Erik's "No-Touch Method" to re-program the BLJB and then start the watchdog or stop petting the watchdog; or use the "software reset" method to put all SFR's back to the reset value, and jump to F800 (I use this method on RD2), or a combination of both.

Which Rs232 signal... none, unless you do something non-standard.

Which other signals... this device can be programmed using CAN ! Isn't that why you are using it ?