The A2 encoder can be used for azimuth or elevation with suitable gearing, but it is easier to use the A2T encoder for elevation because it is an inclinometer (works via gravity rather than being driven by a shaft).

To order these parts you must work up the part number by combining the options you want. The web page gives all the particulars. We do recommend the sealed housings to help keep out moisture. For an example, the Azimuth encoder we have used is a A2-S-B-HS. The part number was derived as follows:
Series = A2, S = SEI buss, B = Ball bearing, HS = Sealed housing.

You could also order the A2-S-HS which uses a standard potentiometer-like shaft instead of ball bearings, for a $10 savings in cost. The part number for the Elevation encoders is A2T-S-HS.

Important: You must specify the buss address of the A2T encoder to be preset to zero (0) when ordering. If you do not, the A2T will have to be 'programmed' to set the address after you have received it and that takes special hardware. The A2-S azimuth encoder normally will be shipped at address 1, which is correct.

When you buy A2 encoders, you can order wires with connectors in the length you need (US Digital part CA-1769. The connector on the wire kit will plug directly into J1. If you are using the absolute encoders for both azimuth and elevation then you will need 3 of the wires and a 'Y' adaptor (CON-MD6-3J).

The 'Y' combines the signals from each of the encoders. You will need to determine the needed length for each side of the 'Y' as well as the length of the main line.

Alternatively you can buy wire, connectors and a crimp tool for RJ11 connectors and make up the wiring yourself. You will still need the Y adaptor if you are using two A2 encoders.