16
W&T
RS232(/RS422/RS485) Multi Computer Adapter
Standard mode
In this mode switching between both data sources is
automatic on a time basis: the data sender that wants to send
something first uses a handshake stop signal or XOFF charac-
ter generated by the T-switch to automatically block sending
from the other source.
If the first data sender inserts a pause, then the second input is
again ready to receive after a settable switching time. The mul-
ti-computer adapter automatically controls the data flow in this
mode using the handshake procedure set on the respective
port.
Transparent mode
The data sender that wants to send something first is
immediately connected to the serial terminal device. All data re-
ceived on the other input of the T-switch are rejected as long
as the terminal device is connected to the first data
sender. Two conditions must be met in order to enable the se-
cond input:
.
The first data source has sent no more data since a
settable switching time.
.
No more data have been received on the second input
since a likewise configurable timeout time.
This mechanism prevents the input from being activated in the
middle of a protocol block and thereby a fragmented data
record from reaching the receiver.
In this mode the Multi Computer Adapter supports only the two
data lines RxD and TxD. The T-switch does not interfere in the
d a t a f l o w i n t h i s m o d e , b u t r a t h e r t r a n s p a r e n t l y
passes the received data from the sender to the respective re-
ceiver. The terminal devices themselves must provide for any
required control of the data flow.
