Oh -- sorry I forgot about the 25,13. This is sent at the head of a ping and a quit request. A ping is typically the first thing you do, so this is probably secretly the "wake up" bytes. Incidentally, this is "%". If you do this on the serial console, you probably can start sending packets to it yourself.

So usually, you would do a {25,13} then send a PingRequestPacket and get a PingResponsePacket (to make sure the Empeg is on the connection), then you would send your CommandRequestPacket (and it would send you a CommandResponsePacket)