Keysight E8402A, E8404A C-Size Mainframes User and Service Guide 43Diagnostic Connector Using the Enhanced MonitorDiagnostic ConnectorThe 25-pin Sub-D diagnostic connector provides access to backplane voltages,power supply and backplane temperatures, and output signals. The pins aredescribed in Table 2-1.Table 2-1 Diagnostic Connector Pin DescriptionsPin # Function Description1 +5 VM +5V backplane voltage monitor (high impedance). (+4.875 Vdc to +5.125 Vdc)2 -12 VM -12V backplane voltage monitor (high impedance). (-12.6 Vdc to -11.64 Vdc)3 -24 VM -24V backplane voltage monitor (high impedance). (-25.2 Vdc to -23.28 Vdc)4 -2 VM -2V backplane voltage monitor (high impedance). (-2.1 Vdc to -1.9 Vdc)5 Rem On Remote power on. See “Using the Remote Power-on Pins.”6 +5 VC +5 VDC source output (1A maximum).7 +12 VC +12 VDC source output (1A maximum).8 +5 V Stdby Input for +5V STDBY (1A maximum for pins 8 and 21 combined).9 GND Chassis ground.10 SysReset * TTL low-true input signal causes system reset, output indicates system reset.NOTE: If you use this pin you must not violate VXI specifications.11 PS Temp Output voltage proportional to power supply temperature (0 VDC at 0 °C, with a rise of10 mV per degree centigrade).12 Ref Temp Output voltage proportional to backplane temperature (0 VDC at 0 °C, with a rise of 10 mV perdegree centigrade). A function of the ambient temperature and load.At no load, Tref ~ 2 °C + ambient. At full load and high fan speed,Tref ~ 14 °C + ambient. At full load and low fan speed, Tref ~ 20 °C + ambient.13 Fans OK * TTL low-true output voltage indicates power supply and backplane cooling fans are operating.14 +12 VM +12V backplane voltage monitor (high impedance). (+11.64 Vdc to +12.6 Vdc)15 +24 VM +24V backplane voltage monitor (high impedance). (+23.28 Vdc to +25.2 Vdc)16 -5.2 VM -5.2V backplane voltage monitor (high impedance). (-5.46 Vdc to -5.044 Vdc)17 GND Chassis ground.18 REM Rtn Remote power switch return. See “Using the Remote Power-On Pins.”.19 V OK * TTL low-true output voltage indicating the +5V, ± 12V, ± 24V, -5.2V, and -2V power supplyvoltages are within ± 8% of its allowed variation.20 GND Chassis ground.21 +5 V Stdby Input for +5V STDBY (1A maximum for pins 8 and 21 combined).22 GND Chassis ground.23 ACFAIL* TTL low-true output asserted by the mainframe power monitor at power down or whenever aloss of power is detected.24 GND Chassis ground.25 RSV Reserved. Used for Timer Verification; refer to Chapter 4.
