Proportional Stick Movement: Every radio made today is proportional. If you move the control sticks 50% of there travel, the servo arm will move 50% of it’s travel.

Travel adjust: This lets you set the amount of servo arm travel in comparison to stick movement. 100% stick travel usually means 100% servo arm travel. If you limit your servo arm travel to say 70% max, then as you move your sticks from 0 to 100% in travel, your servo arm will only move from 0 to 70%, yet remain linear or proportional in movement.

Adjustable Trims: There are usually 4 of these, one to the right or left of each stick and one below each stick. They allow small adjustments to your control surfaces when trimming your plane for level flight. e.g. when flying your plane it has a tendency to roll to the right with no stick inputs (Hands off) from you, moving the aileron trim tab to the left, should allow it to fly level hands off.

Servo Reversing. Servo reversing allows you to change the direction of servo travel. If moving your Rudder stick right moves your servo arm clock-wise. Then using servo reversing switch will make the servo arm move counter clock-wise, while still moving your rudder stick right. This is a must have feature and will come in very handy if a control surface movement is backwards.

Dual Rates. Dual Rates allow you to setup your radio to have different servo arm movement for different switch positions on your radio. These switches are usual located on the upper right and left side of your radio. To use dual rates is helpful and easy to setup. The dual rate switch usually has to positions, up or down. I use the up switch position (higher) for high rates and the lower positions for lower rates. You then setup your radio (look in your manual for your type radio) for full control surface travel on high rates and say 60 to 70% travel on low rates. When you go to fly your plane for the first time, if the plane is to responsive to small stick movements, you can change to low rates. You can also setup your plane to fly differently on different rates. Say high rates for extreme acrobatics and low rates for smother more procession acrobatics.

Model Memory. Computer radios mostly come with some type of model memory. The JR 8103 will store the setup for 10 different models or it can even save 10 different setups of the same model. This is a nice feature if you have more then one plane or what different setups for a plane. e.g. one setup up for a plane to fly 3D, while a different setup of the same plane, might have decreased throws for more precise flying.

Sub Trims. Sub trims allow you to make small adjustments of the servo arm. If one of your control surfaces are slightly off, you can use sub-trims to center it instead of having to make the adjustment from the clevis. You can also center your servo arms is they are off a degree or two. You never want to use this feature to make large adjustments. This may ruin your servo.

Exponential Setup. Exponential or Expo as people call it. Is a computer function that gives you a softer feel around the center positrons of the sticks. It does this by limiting the servo arm travel to a point you setup in the radios functions. With a standard radio setup, the servo movements are proportional to the stick movements. 50% stick movement gets you 50% servo movement. If you setup your radio with say 50% Expo on the elevator, than as you move the elevator sick from 0 to 50% you will only get about 30% of the servo arm movement. As you move the elevator stick past 50% travel you will get the remaining 70% of the servo arm travel quickly. This helps if your plane feels over responsive with small stick movements.

Delta or Elevon Mixing. This is a computer mix (though I have seen it on non-computer radios, rarely) which mixes two channels, aileron and elevator, allowing you to use your ailerons as a elevator at the same time. We call this Elevons. This mix is used on flying wings, delta planes ect. that do not have a conventional tail section. If you have a basic radio with-out this feature, there is a special electronic device that you install between your servos and receiver that will give you this feature.