3.15 How to Set the Serial Port Jumpers
The serial port jumpers on the main logic board (J2604 and J2605) permit the
configuration of the system’s two serial ports for either EIA-432 or EIA-232D signal
levels. EIA-432 levels are the default standard for North American users.EIA-232D
levels are required for digital telecommunication in nations of the European
Economic Community.
For further information, see your Sun Enterprise 220R Server Owner’s Guide.

3.15.1 Before You Begin

Complete these tasks:
Section 2.1 “How to Power Off the System” onpage 54
Section 2.4 “How to Position the System for Service” on page 60
Section 2.6 “How to Remove the System Cover” on page 65
Section 2.8 “How to Avoid Electrostatic Discharge” on page 69

3.15.2 What to Do

1. Locate the jumpers on the main logic board.
A main logic board jumper is identified by its jumper address, labeled on the
board with the letter “J” followed by fournumbers (JXXXX). Jumper pins are
located immediately adjacent to the jumper address. On the board, pin 1 is
marked with an asterisk.
122 Sun Enterprise 220R Server Service Manual ♦January 2000, Revision A