both are real, analogue clock son sticks of dynamite were used in WW1, WW2. we use digital ones now. most of the time a timer's display may not be used, in order to prevent the enemy from defusing it, they remember when they set, and ow long for and leg it. timers are used in almost all explosives, from missiles, to grenades.
remote detonators are very common. and the principle is anything that can receive a signal can be used to detonate an explosive weapon. from a lasers to radio waves to specific sounds, you could attach a phone to a bomb, or a radio controlled car. all that needs to be done is have the electronics of the receiver wired into the bomb.