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QTERM-IV/P40 User's Manual
Beijer Electronics Fax 801-466-8792 Web www.beijerelectronicsinc.com Phone 801-466-8770
If you ordered the backlight, the software commands
shown in Chapter 2 allow you to turn the backlight on and
off. Without the backlight, these commands have no effect.
If you have a wide-temperature display (which includes a
backlight), it will operate identically to the backlit display.
5.5.2
Keypad
The lower-left key on both the 24- and 40-key keypads is a
shift key and has an associated LED to indicate the shift
function (this can be changed by the QDATA file; see
Chapter 3). Above the top row of keys is a row of user-pro-
grammable LEDs (four on the 24-key keypad, and five on
the 40-key keypad).
Software commands and the QDATA file allow you to con-
trol both key clicks (on or off) and key repeat (on or off,
independently programmable for each key).
Every key can be programmed to return an unshifted and a
shifted character or string (up to 255 characters, including
delays, subject to the limitation noted in Chapter 3). Every
key can also be programmed to return an unshifted and
shifted release character or string.
5.5.3
Digital Outputs, dig0 and dig1
The QTERM-IV has two programmable digital output bits
(dig0 and dig1) which can be used to control external
devices. (Note that these are not available on the EIA-422
version due to lack of connector pins.)
Software commands can be used to set these lines high or
low, or to have one or both function as an external buzzer
or horn signal. Both lines are 74HC bus-driver outputs, and
can sink or source up to about 20 mA of current at 0 or 5
volts, respectively.
If either dig0 or dig1 is programmed to act as an external
buzzer signal, it acts as an enable signal: when the line is
low (0 volts), it should shut off the external buzzer or horn;
when the line is high (5 volts), it should turn on the external
buzzer or horn. These lines should only be used to drive an
external transistor which in turn drives the external buzzer.
5.5.4
Buzzer
The QTERM-IV includes an audio buzzer, which is used
for key clicks, for beeping in response to a “bell” character
(^G, 07h) and for programmable-duration buzzing.
For applications in environments that are too loud for the
buzzer to be heard, the digital outputs (described above)
can be programmed to trigger an external device when
buzzer commands are received. (These signals are not
available on EIA-422 units due to lack of connector pins.)
5.5.5
Regulator Option
The standard QTERM-IV requires a 4.8- to 5.5-volt regu-
lated, SELV, DC power source. An optional regulator
allows the QTERM-IV to be operated from a 5.5- to 24-volt
SELV, DC source. The power supply should have a current
limit on its output of 5 Amperes. Limiting may be inherent
to the supply or may be provided by supplementary
devices.
Figure 5-4. Installing the EIA-422 Termination Resistor; Locating the Bar Code Connector.
