They are completely different. The 98. 5 - 2000 trucks are all identical. Round MAP connector w/triangular arrangement pins. Some late 99's and almost all 2000 models used the black, flat 3 pin data port connector. 98. 5 to 99 models used the grey, triangular data port connector. Adapter for this is included. MAP reference voltage is 1. 0v. This is also the box that will work on all current 24v motorhome applications, with a motorhome adapter (plugs into pump connector and supplies data port connector for EZ).
The 2001 trucks use a different MAP connector (flat arrangement, oval plug). Same flat 3 pin black data port connector as 2000. With a MAP plug adapter, this will also work on a 2002. MAP reference voltage is 0. 5v.
The 2002 trucks use another different MAP connector (large, grey, square connector with locking device). Same flat 3 pin black data port connector. With a MAP plug adapter, this will also work on 2001 model trucks. MAP reference voltage is 0. 5v.