Unisys E-@CTION EFP9800 - Manual (Page 214)

EF4270 Emulation Commands
9–10 3255 4073–002
Select
Used for parallel printers only. Causes pin 13 on the 25-pin communication
cable connector to function as the SELECT line. Internal switch pack #3, switch
8 must be set to OFF.
Hexadecimal Decimal ASCII
1B 47 27 71 ESC G
Either Form-In Sensor
This command is not supported and is ignored if received.
Hexadecimal Decimal ASCII
1B 49 27 73 ESC I
Both Form-In Sensors
This command is not supported and is ignored if received.
Hexadecimal Decimal ASCII
1B 4A 27 74 ESC J
Busy Until Buffer Empty
Changes the state of the RTS (Request to Send) line until the buffer is empty.
This command is processed immediately.
Hexadecimal Decimal ASCII
1B 4B 27 75 ESC K