Sending Serial Commands Via Ethernet Controller
Free Virtual Serial Port Over Ethernet
Your Serial.write commands are using pins 1 and 2 of the Arduino to perfrom TTL communication(see the Serial library - it is not related to your Ethernet shield). You'll probably see some gibberish if you open the Arduino serial monitor.The shield will probably not help you. Ethernet is not the same as RS232. Just because you can get two things plugged into each other through converters doesn't mean they know how to speak to each other, as shown in.You should be able to get a TTL to RS232 connector for pretty cheap, but note that if you use pins 1 and 2 you may not be able to upload new code.
Alternatively, you could look into an RS232 shield. DB9 and RJ45 are just connectors.
Interface Ethernet Command
They can be used for anything, not just serial and ethernet. Wiring an rj45 for serial is pretty common, though there's not really a standard for it. You could even run Ethernet though a DB9 if you wanted to be silly, it would probably perform poorly since ethernet has more stringent requirements than DB9 connectors tend to be made to.you need to get the pinout for the camera's rj45 port and wire up a DB9 adapter so you can use it with your RS232 shield. Besides the hardware issues others have pointed out, the two loops that send the commands are off by one.
If you have an array with 10 elements (0-9) and your for loop is testing for less than sizeof(array), then you are not sending the last byte.You should be able to stack your ethernet and rs232 shield, although you should remove the rs232 shield while programming to prevent it from holding the RX line. You can make a cable for your camera by clipping one end off and ethernet cable and soldering on the mating DB9. You should only need TX, RX, and ground. Leave the others disconnected. Do you have the pinout for the RJ45 on your camera?.