first you should start with command POWER_OF This are HEX commands dependent of your card and data stored in it.ġ. OK, communications is based on APDU commands. Sorry because of my poor knowledge of CCID, but I had to make this in a hury. If connection.IsInitialized = False Then Return Sub Connection_NewData (Request As UsbRequest, InDirection As Boolean) Sub SendInRequest(Name As String, Length As Int) Sub SendOutRequest(Name As String, Data() As Byte, Length As Int) 'code from USB project, downloaded here from B4A site If someone can help us both, now is the time. they use T=1, and there is a special way(don't know what) of "packing" APDU in command for T=1. Since you have ACR3901U-S1, I have to admit that I'm stuck there, although they published their protocol. Next command, I guess will be 6F - reading data, can be obtained using Wireshark or a similar app. Now, every command and response has special parts, defined in protocol(length, checksum.), to long to elaborate here. Next command number(increment for each command.) Msg type(62 power on, 61 power off, 6f read data.) first, you need to send to reader power_on command or PC_to_RDR_IccPowerOn(search google) like this
Communication is based on APDU commands, posting them here can not help you since every card is different. So, I have managed to read data from the smart card using Omnikey 3x21 reader(+otg cable). Only started with CCID, but I think I can put you in the right direction.
Is this something that the various Bluetooth and Serial libraries can handle? The app will need to communicate with the Smart Card using APDU commands using T1 protocol in order to sign the invoice using a stored certificate on the smart card. I have seen another thread that uses the headphone jack to read a Square Card Reader but I am looking at a Bluetooth unit from Advanced Card Systems that has Android and IOS compatibility due to the mechanical issues associated with mounting a device directly to a phone or tablet using a headphone jack or USB connection.
Currently there is a Free alternative that communicates with a central server over the internet to do this, but without a reliable internet connection the shop will be non-compliant and face either very expensive alternate solutions or fines. This is to be a very low cost solution for village shops where internet connections are less reliable so it will be a standalone device to "fiscalize" invoices for Tax office compliance.
I have an opportunity to build an app for the Samoan tax authority that is a standalone Simple POS/Register but it needs to interface with a Smart Card reader.