QTERM-IV/P40 User's Manual
35
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5.4.3
5-volt Buffered Interface
When used to communicate with another 5-volt Buffered
device, the QTERM-IV can operate at distances up to 5
meters. The advantage of the 5-volt Buffered QTERM-IV
is that it is lower power than the EIA-232 version and uses
the same 5-volt logic levels as come directly out of a UART
(i.e. the idle state is at 5 volts, and the active state is at 0
volts).
Although the signal levels are the same as at a UART, the
transmit and receive lines are buffered and can be con-
nected to live signals whether or not the QTERM-IV/P40 is
powered (turned on).
5.5
Other QTERM-IV Hardware
5.5.1
Display
The QTERM-IV display is a 4-line by 20-character
supertwist unit. The ASCII character set and eight user-
defined characters can be displayed. Hosts which transmit
8-bit data can also display an additional 64 characters
including Greek letters, katakana characters, non-English
alphabetic characters and math symbols.
Appendix B is a chart which shows what the QTERM-IV
does with every possible 8-bit value it can receive. Note
that the ASCII portion of the chart (the first 128 characters)
is similar, but not identical, to the true ASCII chart shown
in Appendix A.
Table 5-1: QTERM-IV Pin Assignments.
Handheld
6-pin Modular
Handheld
DB9
QTERM-IV
Panel Mount
2 mm
QTERM-IV
232/5 Volt Buff-
ered Function
QTERM-IV
422
Function
QTERM-IV
485
Function
1
3
1
receive
+receive
dig0*
2
6
2
dig1*
-receive
dig1*
3
2
3
transmit
+transmit
RTx+
4
1
4
dig0*
-transmit
RTx-
5
9
5
+V†
+V†
+V†
6
5
6
ground
ground
ground
Tx and Rx directions are with respect to the QTERM-IV
*these lines are optional; see section 5.5.3
†no connection with battery back units
3DQHO0RXQWPP
&RQQHFWRU
+DQGKHOGSLQ0RGXODU
&RQQHFWRUV
&RQQHFWRUV
+DQGKHOG'%
3OXJ
0DOHRQFDEOH
)HPDOHRQ47(50
-DFN
3OXJ
Figure 5-3. QTERM-IV Connector Pin Numbering.
