Installation Instructions

SIM5216A _HD_V1.02 Hardware Design

SIM5216A _HD_V1.02 26.08.2010

Figure 12:

Interface of serial ports

Serial port

z Port/TXD @ Client sends data to the RXD signal line of module

z Port/RXD @ Client receives data from the TXD signal line of module

All pins of all serial ports have 8mA driver, the logic levels are described in the following table

Table 8: Logic levels of serial ports pins

Parameter Min Max Unit

Logic low input 0 0.3*VDD_EXT V

Logic high input 0.7 *VDD_EXT VDD_EXT +0.3 V

Logic low output GND 0.2 V

Logic high output VDD_EXT -0.2 VDD_EXT V

Note: VDD_EXT=2.6V, is module internal IO reference voltage.

SIM5216A provides an AT command (AT+CSUART) to support Null modem. Null modem mode

uses two lines (RXD, TXD (GND not comprised)) to setup communication between devices. The

lines connection is shown as below.