After entering either 'A' or 'N', the computer will immediately beginning programming the chip. When I first tried this, I thought something went wrong, as the teletype started making some chattering noises. Apparently this is normal and serves as a sort of audible indication of the programming as the chattering matches the blinking of the programming LED on the back plane.
The Mod-8 burns an EPROM as follows. Instead of burning the entire chip and then verifying it, it will burn each byte individually and verify the contents are ok before moving on to the next byte. If the burn was not successful, it will re-burn the byte and verify it again. It will continue to do this until the burn takes. Healthy EPROMs take slightly less than a minute to burn, whereas poorer chips may take several minutes to burn, as the number of re-burns will be higher. Interestingly enough, these chips are only mildly warm to the touch when they are finished, much different than what I noticed with my 1702A EPROM burner for the PC.
Not only can you write data to the EPROM in the ZIF, but you can read it as well. Monitor-8 uses memory locations 200000-200377 to access the EPROM data. You can also use 300000-300377 as well. Notice these ranges are well outside the 16 kB address space normally accessible to the 8008.
If using Monitor-80, the above address locations could represent real memory locations in RAM (or ROM), so to read EPROM memory, you use P000-P377 instead.