The Epoch 35 is built specifically for Survey Pro and can not be used with Trimble Access (as they now call it). The Epoch 35 is a great unit featuring both GPS and GLONASS. It is priced right and easy to use. However, it has been discontinued and along with that so have parts. Stick with a new EPOCH 50, same thing, however, the rovers have integrated radios with both transmit and receive capabilities allowing you to use it as a base or a rover. It also features a Trimbl;e brand board, instead of the Novatel board in the Epoch 35. It also has L2C and L5. Priced very close.