If anyone is looking for a cheap way to do this, you can pick up a UBlox 6M on an interface board for less than $7 on ebay (add a couple more dollars if you want a US seller with faster shipping time) and dig up an old phone cable with 4 wires. The latter was the hard part for me since I haven't had a landline for 10 years - finally found one wrapped up around an old DSL modem. The wiring diagram early in this thread is correct, but use pin position and not wire colors - in mine the wire colors were reversed: power was red/black but black was positive. The UBlox is perfect with 3.3v VCC and IO. Don't waste your money on a UBlox 7 or 8, these are newer and more powerful, can do multiple constellations (GLONASS etc.) and give more precise positions, but you don't need it in this application. The 6M is a very good module, I get solid lock inside a house with a metal roof. Look carefully before you buy one of the pre-made sensors. These are tempting because they look good but most are configured to communicate via I2C and have a built-in magnetometer for use on drones.