Why does my power cord on my echo map uhd 93 sv have 4 wire the positive and negative but why is there a brown and blue wire?

4 minutes ago, Turkeyslayer75 said:

Why does my power cord on my echo map uhd 93 sv have 4 wire the positive and negative but why is there a brown and blue wire?

"Blue and Brown¹ (Optional) - The Blue wire is the Tx (Transmit), and brown is the Rx (Receive) wire. These wires are used only for Garmin Data Sharing between the Striker and the ECHOMAP² series devices. If these wires are left disconnected, Garmin suggests clipping the stripped tinned ends back to the insulation."

 

https://support.garmin.com/en-US/?faq=xXS5gKb6rsA6hKT97PfrJ6

Exactly what he said ^^^^