User's Manual
Landis+Gyr Chapter 1 - Product Overview
UtiliNet SCADA Single Board Radio 98-1546 Rev AA 9
Pin 2 (LPP TX) and Pin 3 (LPP RX)
These pins are used to interface with the device's LAN Packet Port. These pins are driven at TTL
levels from 3.3 to 3.4 VDC.
Baud rates on this port default to 9600 bps, but using RadioShop are configurable up to 38,400 bps.
To reduce chances of electrical damage, a 10Kohm series resistor is placed in-series with the pin
which limits the drive current capability of this pin.
Stray physical capacitance on this circuit should be kept below 250[pF].
Pin 4 (DIGITAL_IO1) and Pin 11 (DIGITAL_IO2)
These pins are general purpose digital I/O lines and are driven at TTL levels from 3.3 to 3.4 VDC.
If not used, they should not be left unconnected and should be brought low connecting the pin to a
common ground.
If used, these pins must be driven to a valid logic high or low and not left at intermediate voltages as
this will result in indeterminate logic values and may damage the device.
Pin 5 (ANALOG_IN1) and Pin 10 (ANALOG_IN2)
These pins are analog inputs to the device. Voltages must be scaled to the 0 to 2.50 VDC range. The
UtiliNet SBR returns the DC voltage as HEX values in the memory locations as described in
“Analog Input Functionality” on page 31.
The value returned is shown in the table below.
The DCW that reads the memory location returns the HEX value, in the range of 0-03FF, from which
the user must convert to decimal and then using the formula can obtain the voltage value.
These pins are NOT directly connected to an RS-232 interface on a computer, and where such a
connection is necessary, the developer must purchase a TTL to RS-232 3.3 VDC converter which
is powered externally and NOT via the pins or the RS-232 connection on the computer.
Table 1-2. Voltage Conversion
Voltage = (Decimal value/1023) * 2.5
HEX Read Actual Voltage
0000 0
0006 0.01
006B 0.25
0119 0.68
0253 1.44
0382 2.19
039F 2.26
03C7 2.36
03F1 2.46
03FD 2.49
The Analog I/O pins may be configured as Digital I/O pins or as General Purpose I/O
pins, if desired.