L3 Systems KeyAT, Руководство пользователя

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KeyAT Keyboard Port Adapter
L3 Systems 23 5/19/2007
Multi Drop Operation
If the DIP switch address setting is not zero, KeyAT looks for
an address select prefix to any buffer received. The address
must be the first byte of the transmission and the high bit set.
Address 1 is hex 81, Address 2 is hex 82. If you send a
command to address 80, all KeyATs will read it.
When sending data to the KeyAT in multi-drop mode, the
KeyAT will send a single byte colon character when the
message is received. This does not mean that another buffer
can be sent! The KeyAT sends the colon character to signify
that the message was received and that the host can go on to
talk to other devices. If a proper delay cannot be assured, it is
recommended that you poll the device until it responds before
sending another buffer.
RS485 Wiring
If you are using RS485 connections to the KeyAT, be careful
that all devices be referenced to the same ground.
Improper
grounding can cause damage to the circuitry
,
and will not
allow the transmitter to operate.