User's Manual

Boomer II User Manual & Integrator’s Guide _________________________________________________Installation
BM210012WT27 39 Wavenet Technology
LED Output Lines
In addition to the on-board LEDs there are three signal lines (Low
Battery, Message Waiting, In-range), which are controllable by the
modem for connection to an external LED. Each line has a 33Ω series
resistor and clamp diode to the internal supply line for protection. It is
recommended a series resistor be used with the external LED to limit
current accordingly. The electrical interface capability, equivalent
circuit and operation of these lines is summarized in the tables below:
LED Output Lines Equivalent Circuit
LED Interface Electrical Characteristics
Parameter Range Low High
Output Voltage 0 – 3.3 V 0.5 V (max) 2.3 V (min)
Output Current 3.2 mA (max) 1.6 mA (min)
Note: DCD and INRANGE outputs share the same output line from the
microprocessor and therefore the combined current consumption of
that line must not exceed 2mA.
LED Interface Definitions
J1
Pin #
Signal Description Signal Active State
13
LED
0_
MSGWTG
Message
waiting
Output Low when message waiting
14
LED
1_
INRANGE
In range Output Low when modem in-range
15
LED
2_
LOWBAT
Low battery Output
Low when battery is less than
3.5V,
High when battery is greater
than 3.6V
Low Battery
The Low Battery signal is held active low whenever the supply voltage
drops below an acceptable level (less than 3.5V) and deactivated when
the voltage level becomes acceptable again (greater than 3.6V). The