Communication to battery regulator

I am wanting to set up communication between an arduino and a battery charger regulator and don't know if the project is feasible or where to start. I will set up a touchscreen with it later. The regulator is http://www.manzanitamicro.com/products?page=shop.product_details&flypage=flypage.tpl&product_id=54&category_id=22. All I want to do know is send a ping command and receive a signal for now. The chipset thats on the board is a atmel 168. The manufacturer of the regulator(not distributor) sent this about the communication. The 12-15V levels on the EviBus signals WILL DESTROY your Arduino if you try to hook them up directly! The pins that are directly usable are the RX/TX lines, which are used for the USB on the Arduino. In order to use>> the Twi interface pins, you would have to bit-bang the async interface. Yes the TWI interface is serial, no it is not async like rs-232. The Rudman bus uses async signaling but with different levels. If you are going to use the Arduino, you will have to use the Rx/Tx lines IO0 and IO1, which make downloading new software a bit>> troublesome, but you can get there. The signaling is half duplex (party line) async like RS232, but with a different hardware interface. I previously sent you a schematic of the> interface. Undriven, (space), the two lines are between 10 and 15V> apart, and driven, (mark) they are about 2V apart. There is no "ground" reference. One advantage of this is that you can use a normal terminal> or terminal emulator program to talk to the Rudman Bus devices: 9600> Baud, 8 bits, no parity, 2 stop bits. If all you want to do is blink the lights, the command to use is the "Lights" command: "01l." followed by a carriage return.

Do you have the full version of the manufacturer's answer, including your questions?

To me, it sounds like you have two choices: use an async serial interfaces on the two specified contacts or use the I2C interface (that what he meant with TWI, Two Wire Interface). The I2C interface is serial but uses a master/slave communication scheme, so the slave can only send data to the master if the master is requesting it explicitly.