User's Manual

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USERS MANUAL
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Document number Revision
1/198 17-5/FCP 101 3317 Uen A
5.3 Data Communication and Control Interfaces
The serial data and control interfaces consist of the following :
USB
P_EN
5.3.1 USB Interface
Function: USB data communication port
Description: USB transmit and receive port for data communication between
modem and host.
Pin Numbers: 1, 2
Signal Names: USB_DP (2) [modem
host]
USB_DN (1) [modem
host]
If not used: Required
Details:
Power to the USB interface is provided by the 3V3 input from the host.
5.3.2 P_EN
Function: Power Enable
Description: Modem power enable control from host
Pin Numbers: 24
Signal Names: P_EN [host
daughter card]
If not used: Required
Details:
The power enable signal is provided from the host application and is routed to the
switching regulator shutdown input and also to the REG_EN (regulator enable) pin on the
modem. Assertion of this pin will initiate power up. The P_EN pin is active high and has
to be maintained continually in order to keep the modem powered.