Siemens SIMATIC Box PC 820, Manual

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Box PC 820 / PC FI45 V2, Manual
A5E00051531-03
2.8.29 Description of the Switch Positions S2 (TTY, BIOS)
Switch Settings
The following switch settings are for your information only. They are set in the fac-
tory and may not be changed.
x means that this switch is irrelevant for the funtion described.
BIOS Source File
S2 (3) Function
off Boot EPROM activated (standard setting)
on Boot EPROM not activated (boot module required)
TTY Setting S2
S2 (1) S2 (2) Function
on on active TTY interface (standard setting)
off x TTY transmit loop, isolated from power source
(passive setting)
x off TTY receive loop, isolated from power source
(passive setting)
Setting the Front Side Bus Frequency S2
S2(4) ISA Bus Frequency PCI Bus Frequency CPU Bus Frequency
on 8.25MHz 33MHz 66MHz
off 8.25MHz 33MHz 100MHz
1)
1)
Frequency is dependent on the processor and is set automatically e.g. 100 MHz for
Pentium III.
Motherboard
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