USR-K2 Hardware Manual
Jinan USR IOT Technology Limited
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1.2. Pin Definition
PIN
Name
Signal Type
Definition
1
NC
NC
Not available
2
NC
NC
Not available
3
LINK
O
Can be used to indicate TCP connection status. After
establishing TCP connection and enabling LINK
function, led LINK will light.
4
RST
I
Inputting low level over 300ms to reset the module
5
485_EN
O
RS485 receiving/transmitting control pin, high level to
enable transmitting.
6
Reload(CFG)
I
After module powering off, pulling down Reload pin to
0V, then powering up, keeping Reload pin 0V over five
seconds and pull up Reload pin(3.3V), module will
restore default settings. Reload pin connects to
internal 10K Ohm pull-up resistor.
7
L
O
Ethernet interface L pin
8
RXD
I
Serial port receiving pin(3.3V, TTL level) which needs
to connect to external 10K Ohm pull-up resistor.
9
TXD
O
Serial port transmitting pin(3.3V, TTL level) which
needs to connect to external 10K Ohm pull-up
resistor.
10
GND
P
Power ground
11
VCC
P
3.3V VCC
12
L
O
Ethernet interface L pin
