ISO8583包（简称8583包）是一个国际标准的包格式，最多由128个字段域组成，每个域都有统一的规定，并有定长与变长之分。8583包前面一段为位图，用来确定包的字段域组成情况。

其中位图是8583包的灵魂，它是打包解包确定字段域的关键， 而了解每个字段域的属性则是填写数据的基础-ISO8583 packets (8583 packets) is an international standard format, and up to 128 field domains, each domain has a unified, and the fixed-length and variable-length one. 8,583 packages for spaces in front of a map, used to determine the packet domain composition of the field. Bitmap which is the soul of 8583 packet, it is unpacked and packed up to determine the key field domain, and the domain of each field attribute is the basis for completing the data