into the register. JMS JuMp to Subroutine at the address specified in the following 12-bit word. JMR JuMp to RETURN from a subroutine, to ADDRESS+1 of the most recent JMS. effectively, in modern terminology, JMS pushed the current instruction address onto a "stack" and JMR popped the return address. In effect, JMR is actually a specific TRR in which PC2 is transferred to PC1. SKP SKiP is a TRR in which PC1 is incremented by 1. There were also TEST instructions (Test if something is ON or OFF) and SET instructions (SYN Set "Y" oN, SYF Set "Y" ofF). Software The original PDP-14 required that programming be done by DEC. Subsequently, software development for the PDP-14 was done on another system, the PDP-8. A PDP-8 program named SIM-14 allowed for simulating the PDP-14. Photos PDP-14 PDP-14's M740 Instruction decoder module PDP-14's M745 PDP-8 Interface See also PDP-16 References External links PDP-14 User's Manual includes information about interfacing options DEC computers Industrial_automation Industrial_computing Programmable_logic_controllers