For the 340, the switches are - from right to left (right switch should
have the dot):
        MEN - RS232 Modem enable. [I think this is RTS/CTS -- PMM]
                                   1 = modem lines enabled (shipped setting) 
                                   0 = modem lines disabled
        REM - RS232 Remote terminal enable
                                   1 = Remote Mode
                                   0 = Local Mode (shipped setting)
        LAN - Lan Local/Remote
                                   1 = Remote Mode (not currently used)
                                   0 = Local Mode (shipped setting)
        SC - Internal HP-IB System Controller
                                   1 = System Controller (shipped setting)
                                   0 = Not System Controller