Can anyone answer how BCD data is usually calculated for fields what have subfield values?
I don't mean in terms of code, as I have that part nailed down.
What I mean is say I have field X, which is to be sent containing data for 5 sub values. The field is BCD, but would each sub-value be converted to BCD and then appended to field X or would they be added to field X in the clear and then converted as a whole to BCD?
Can't find a clear answer anywhere... not even in the message spec I'm working off of oO
Cheers, Mike K
You have to know the format of field X and the format of subfields. Let me give you an example.
Assuming that you would like to transmit emv data form pos to Host using a field X.
A format for field X is described below.
Length Attribute 3 bytes LLL Length of data to follow
Subfield 1 var bytes First Additional subfield
Subfield 2 var bytes Second Additional subfield
...
Subfield n var bytes nth Additional subfieldThe structure of each additional subfield is as follows
Tag Name 2 bytes
Tag Length 1 byte
Tag Value ..bytes