protected BBEncoder init(char opcode, long sequence)
{
BBEncoder enc = new BBEncoder(1024);
enc.init();
enc.writeUint8((short) 'A');
enc.writeUint8((short) 'M');
enc.writeUint8((short) '2');
enc.writeUint8((short) opcode);
enc.writeUint32(sequence);
return enc;