The decimal number you receive (3685287048) is DBA90488
in hexadecimal representation. Thus, the keyboard-emulation reader gives you the first cascade-level part of the tag UID (see ISO/IEC 14443-3 for reference).
For a tag with a 7-byte UID zzyyxxwwvvuutt
(in your case 04A9DBA2853280
), the ISO 14443-3 anti-collision has to cascade levels. The UID in cascase-level 1 is 88zzyyxx
(in your case 8804A9DB
). 88
is the cascade tag which is used to distinguish (i.e. produce collissions between) 4-byte UIDs (which use only a single cascade-level) and tags with longer UIDs (7/10-byte). The UID part in cascade-level 2 is then wwvvuutt
(in your case A2853280
).
As your reader stops the enumeration procedure after cascade-level 1, it detects only the first part of the UID (including the cascade tag): 88zzyyxx
. This translates to the decimal number:
xx_h * 2^24 + yy_h * 2^16 + zz_h * 2^8 + 88_h
In your case:
DB_h * 2^24 + A9_h * 2^16 + 04_h * 2^8 + 88_h =
219 * 2^24 + 169 * 2^16 + 4 * 2^8 + 136 =
3674210304 + 11075584 + 1024 + 136 =
3685287048