RS3000 (VIP) Keyless entry not working in Camry 1997

I have Toyota 1997 Camry LE model with 4 Cylinder. I got it in 1997 with RS3000 VIP security system with keyless entry. From last month it stopped working. I thought battery in the remote needs to be cahnged, I changed it , the red light in the remote is blinking but door is not unlocking. Then, I found the security system below the dash board (on the left side of steering) is not blinking. So, I don't know what went wrong. While locking and unlocking it used to make that Chirp noise and it was stopped making that noise for last 6 month and now it stopped working. I am openign and locking manually with key. Any help could be appreciated to fix the above problem with keyless entry.

Thanks in advance,
ToyotaCamry1997