Wavenet Technology Pty Ltd. BM2900D 用户手册
Installation_________________________________________________ Boomer II User Manual & Integrator’s Guide
Copyright Wavenet Technology © November 2003
32
BM210012WT37
Modem On/Off Control
The modem on/off input line (HOSTPWR_ON) is an active high input
signal and is fitted with a 33Ω series resistor and clamp diode to the
internal supply line for input protection. Internally it is passively pulled
low (after the series resistor) via a 56kΩ pull-down resistor to ground
and is asserted with an actively driven high signal. To turn the modem
off it must be actively pulled low to ground. The electrical interface
specification and equivalent circuit is as follows:
The modem on/off input line (HOSTPWR_ON) is an active high input
signal and is fitted with a 33Ω series resistor and clamp diode to the
internal supply line for input protection. Internally it is passively pulled
low (after the series resistor) via a 56kΩ pull-down resistor to ground
and is asserted with an actively driven high signal. To turn the modem
off it must be actively pulled low to ground. The electrical interface
specification and equivalent circuit is as follows:
Modem On/Off Control Equivalent Circuit
Modem On/Off Control Electrical Characteristics
Parameter Range Low High
Input Voltage
0-3.3 V
OR
0-5V
0.4 V (max)
1.0 V (min)
Input Current
400 µA (max)
100 µA (max)
It is acceptable to drive this input with a NPN transistor or N-channel
MOSFET connected to ground with a 4k7Ω pull-up resistor to 3.3V
Warning: When the modem is turned off using the HOSTPWR_ON
signal and HOST_3.8V power is removed, all other signals connected
to the Data Interface Connector should also be turned off or set to 0V
otherwise the modem may remain powered on via these signals.