Hi, I have a Nuvi 2598LMTHD and a Nuvi 2689LMT. The 2598LMTHD came with a GTM 60 power cord and the Nuvi2689LMT came with a GTM 20 power cord. I was wondering if these cords were necessary to receive traffic signals. I thought I saw some were that if model number was printed on the receiver under the mount then they had the traffic receiver built in and didn't require a separate receiver. I'm going to use a back up camera with the Nuvi 2689LMT because it's going on our truck. I'll be adding an extra camera to our travel trailer since the Nuvi 2689LMT will handle up to four cameras. Thanks, Jim