Cash Drawer and printer issue

We have a few customers who are having issues with their cash drawers since the update to version 15 (it may have started before that and just not been reported to us.) One of the customers uses a serial cash drawer hooked directly to the computer, they use Generic Text Printer for there driver we use to be able to just send the open code to it. Now if we try it will open their drawer once and not again, and shut down all there other printers until they log off all sessions and log back in, then it will work once again. If we send an empty document to the printer it will keep working with out having to log off and on again but the drawer will trigger to open 20+ times. Sounds like a machine gun going off. The other customer is using an iTherm receipt printer they have a very similar problem. Again we use to send the the open code directly to the printer which in return would open the drawer. Now it will open once and not again and also shut down all their printers and will not allow them to print on any printer until the log off all sessions and log back in. With the iTherm printer we can tell it to open the drawer at the beginning of a print but now it will open on credit card sales and reprints. In order to open it with out a sale we have to send a blank document to it to open and that will print about 1/2 inch of paper every time they do this.
My question is, is there something that we need to configure on the server side or client side to get it so we can talk directly to the printer again? Or is there some other way to get this working again?
Thanks