while you send iso8583 track2 to server, it can be ascii or BCD. in some cases its BCD.

hex of '=' character is 0x3d . in my experience '=' character should be nibble of 0x3d which it is 0xd or 12 in decimal.

e.g: 0x3d & 0x0F = 0xd;

hope it can be helpful.