Serial Interfaces; Figure 15: Rs-232 Interfaces - Siemens MC45 Manual

MC45 Hardware Interface Description
P R E L I M I N A R Y

3.5 Serial interfaces

MC45 offers two serial interfaces, each operating at 2.65V level. All RS-232 signals on the
board-to-board connector are low active. Both interfaces are implemented as a serial
asynchronous transmitter and receiver conforming to ITU-T RS-232 Interchange Circuits
DCE.
The GSM engine is designed for use as a DCE. Based on the conventions for DCE-DTE
connections it communicates with the customer application (DTE) using the following
signals:
RS-232(0)
·
Port /TXD @ application sends data to the module's /TXD0 signal line
·
Port /RXD @ application receives data from the module's /RXD0 signal line
RS-232(1)
·
Port /TXD1 @ application sends data to module's /TXD1 signal line
·
Port /RXD1 @ application receives data from the module's /RXD1 signal line
MC45
(DCE)
MC45_HD_01_V00.02a
/TXD0
/RXD0
/RTS0
/CTS0
/DTR0
/DSR0
/DCD0
/RING0
/TXD1
/RXD1
/RTS1
/CTS1

Figure 15: RS-232 interfaces

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Application
(DTE)
/TXD
/RXD
/RTS
/CTS
/DTR
/DSR
/DCD
/RING
/TXD1
/RXD1
/RTS1
/CTS1
12.08.2002