I have done something wrong when I went into my programming of my JCM Gold G2-11 and now it just beeps when I try to enter anything when I try to use it normally. It is not the battery, that was just replaced and the machine had a full service.
I think you need to log on with this model when you have turned the key. If it has a clerk button, try logging on with a clerk code eg 1 CLERK (on some models you use CLERK 1 CLERK)