The RS$-232$ interface standard specifies the method of connection of two types of devices.

a$)$ Name the acronyms for the types.

b$)$ Expand the acronyms into words.

c$)$ Briefly describe their functions.

d$)$ Give an example of each type.

e$)$ Specify the pin numbers $($for a $25-$pin connector$)$ on which each type receives and transmits data.