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OUTPUT CONFIGURATIONS
The other function of J2 and J3 is to configure the
communication channel in half or full duplex mode. Half
duplex operation is achieved by connecting pins 4 and 8
of the jumper block (figure 23). This allows the
transmitter to be enabled and disabled using the data
terminal ready (DTR) output in the modem control
register. Full duplex operation is restored by removing
the jumper on pins 4 and 8 (figures 21 and 22).
Jumper J4 selects the level of DTR that enables the
transmitter outputs. When the enable control line is
connected to +DTR (factory configuration), writing a
logic 1 to the DTR bit location in the MODEM control
register enables transmission. Writing a logic 0
disables transmission. In this configuration, trans-
mission is disabled on power-up.
Enable1
-DTR --+ | +-- +DTR
+-----------+
4 | o o--o | 6
J4 1 | o o--o | 3
+-----------+
-DTR --+ | +-- +DTR
Enable2
To maintain compatibility with some other Quatech
products, the enable control line can be connected to -
DTR. In this configuration, writing a logic 0 to the DTR
bit location in the MODEM control register enables
transmission, logic 1 disables transmission. In this
configuration, transmission is enabled on power-up.
Enable1
-DTR --+ | +-- +DTR
+-----------+
4 | o--o o | 6
J4 1 | o--o o | 3
+-----------+
-DTR --+ | +-- +DTR
Enable2
CAUTION:
When operating in half duplex mode, the
transmitter must be disabled before receiving
any information. Failure to do so will result
in two output drivers being connected together
which may cause damage to the DS-2000, the
computer and the peripheral equipment.
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