Hello,
I want to interface fingerprint module SM-630 with arduino and tell me how to write command
You need to ask much more and better questions, and also point to or provide more information.
Where is information about the Fingerprint module?
What actions do you want to take?
What decisions do you need to make?
Then you can start thinking about Software Sketch code....
Duplicate post deleted.
i used SM 630 fingerprint module...
and we want to store and interface, fingerprint of the users in pc through arduino...
here i attach the datasheet of our fingerprint module SM630...
pls reply me as soon as possible as we want to interface with arduino... 
SM-630.pdf (132 KB)
TTL serial, well-documented command set with examples, wide voltage range so should be simple.
I'd start by testing the "read product flag" command.
What's holding you up?
i didnt get what u say AWOL....can u elaborate again..??
TTL serial, well-documented command set with examples, wide voltage range so should be simple.
I'd start by testing the "read product flag" command.
The device has a TTL serial interface, so the connecting it to an Arduino should be simple. Don't forget the 10kohm pullup mentioned in the datasheet.
The command set is simple and well-documented, and examples are provided.
The supply voltage is within the Arduino's range.
There is a command called "read product flag", which looks like a sort of "Who are you?" command, so that would be the one I'd try first.
You might want to look at the SoftwareSerial library to begin with.
I am also in same trouble as sunnyshah1992, What is the way to interface SM630?
Basically how to check the working functionality of SM630?
Interface Protocol:
Standard serial interface （TTL level）
Read the datasheet. Is that so hard to do ? If you can't be bothered to read the datasheet why should we spend the time to help you ? Prove that your read the datasheet first.
4.3 Coding Method
The communication between HOST and Module must be coded as Communication
Packet.
One communication packet includes the following:
Packet Head（2 bytes）
Packet flag（1 byte）
Packet length（1 byte）
PDF created with pdfFactory Pro trial version www.pdffactory.comMiaxis Biometrics Co., Ltd. http://www.miaxis.com
第 12 页 共 25 页
Packet Content（N bytes）
Check sum（1 byte）
Packet head：0x4D 0x58
Packet flag：
0x10：command packet
0x20：data packet
0x21：last packet
0x30：response packet
Packet length：
Length of the Content in packet
Packet content：
Content of packet
Check sum：
Low 8 bytes of the SUM from packet head to check sum.
and tell me how to write command
You didn't say "PLEASE"