DE910 Series Hardware User Guide
1vv0300951 Rev.9 – 2015-05-11
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 48 of 77
NOTE:
According to V.24, RX/TX signal names are referred to the application side. Therefore, on the
DE910 side these signals are in the opposite direction: TXD on the application side will be
connected to the receive line (here named TXD/ rx_uart ) of the DE910 serial port and vice
versa for RX.
NOTE:
High-speed UART supports up to 4Mbps. Please refer to the AT command User Guide in
detail.
WARNING:
Consider a mechanical design and a low-capacitance ESD protection device to protect DE910
or customer specific requirements from ESD event to UART port (M15, N15, P15 and L14).
8.2.
Modem Serial Port 2
Serial port 2 on the DE910 is a +1.8V UART with only the RX and TX signals.
The signals of the DE910 serial port are:
Pin
Signal
I/O Function
Type
D15
TX_AUX
O
Auxillary UART (TX Data to DTE)
1.8V
E15
RX_AUX
I
Auxillary UART (RX Data from DTE)
1.8V
NOTE:
In order to avoid a back powering effect it is recommended to avoid having any HIGH logic
level signal applied to the digital pins of the DE910 when the module is powered off or during
an ON/OFF transition.
8.3.
RS232 Level Translation
In order to interface the Telit DE910 with a PC com port or a RS232 (EIA/TIA-232)
application, a level translator is required. This level translator must:
Invert the electrical signal in both directions
Change the level from 0/1.8V to +/-15V
