The 4700 series of Control Units are specialized controllers sold by IBM, typically to banks. This series includes the 4700, 4701, and 4702. The 8770 Control Unit is also a specialized controller sold by IBM to finance companies. These are specialized controllers, and there is no stated support for them with MacDFT.
One solution might be to set MacDFT up for CUT mode emulation. When MacDFT is in CUT mode, much of the terminal and communication processing is done by the controller. In this case, this may help eliminate or minimize any keyboard mapping discrepancies.
It is also possible there is an RPQ installed, which is a specialized remapping program. When using RPQ, you can usually go back to any "default" key by pressing "Alt" and the appropriate key. For example, to execute a Clear when using a RPQ, press Alt and Clear. With MacDFT, because the Alt key isn't mapped, you'll need to assign a key to the Alt-Clear sequence using the Keyboard mapping feature. This is documented in Chapter 5 of the "MacDFT User's Guide."
Other companies use a different strategy with RPQs. DCA sells different keyboard layouts for the Macintosh for some of the different RPQs commonly used.
If no RPQ is installed, you might be able to remap any errant keys using the keyboard mapping feature anyway.