The Bronze + Trio has the following inputs:
Speed log input
Echo sounder input (coaxial cable)
NMEA 0183 (e.g. for GPS data input)
It does not have a water temperature input.
It can also send NMEA 0183 data.
The speed log, NMEA IN and NMEA OUT connections are all in a single mini-DIN plug which is supplied with the unit, with a cable tail ready for you to wire up. Wiring diagrams are in the user manual.
I used an old Garmin GPS III to send NMEA 0183 data to the Echopilot display, it worked fine. The Echopilot showed GPS time, the name of the selected waypoint, the distance to go, course, track, xtrk, speed and the bearing to the waypoint. You could also select a page on the Echopilot to display the raw lat/long position. I found it easy to set up and use with my GPS - it was plug and play really.
The speed log interface was a bit more complex and needed calibration, but that was fairly easy, Depth sounder just needed the sounder frequency to be set (200kHz for the P32 I used).
I found the speed log was not particularly linear on my boat, compared to the GPS speed anyway. In the end I calibrated the log for planing speeds and lived with the fact it over-read at displacement speeds.
If you have a look online, or contact echopilot direct, you should be able to find some screen shots for the Bronze + Trio Display.
Re the connector, I will have to find the number for you. It was made by Conxall but I cannot remember the part number.