Can anyone help with Redpark iOS C2-TTL Cable?

Hello everyone! I am working on a project and really need some help because I’m under a deadline.

I purchased the new Redpark iOS C2-TTL cable to use with Arduino - this cable doesn’t require the DB9 Serial adapter to convert the RS-232 signals to TTL since it’s the newer version. I have the pin outs for the Redpark cable, RTS, RX, TX, DTR, CTS, GND (orange → black), but I don’t know how this cable is supposed to connect to the Arduino board. I’ve looked online and even tried doing the sample projects to blink an LED from the iPhone, but nothing is happening. I don’t think I have the cable hooked up correctly to the Arduino for it to work so I was wondering if anyone can help confirm how this cable is supposed to connect to the Arduino Uno board.

I tried to email Redpark for support, but they referred me to a project that Make Magazine did for the RS-232 cable (the older version that required the DB9 adapater). Here is the link:

Here is another link to another sample project that I found: The Daily ACK: Connect your iPhone to the real world

I couldn’t get either of these sample projects to work since they are using the RS-232 cable and don’t explain how to connect the iOS cable to Arduino, so I was hoping to get some help here.


Has anyone even used the new C2-TTL cable yet?

I figured it out! The Redpark TTL cable only needs to have the RX, TX and GND pins connected to Arduino for the cable to work. The TX on the cable goes to pin 0 (RX) - the RX on the cable goes to pin 1 (TX) - and the GND goes to ground of course.

The trick is the way the cable is connected it seems. You can't plug the cable in to your iOS device while it's connected to your Arduino board or the cable won't work. You have to unplug the cable on both ends, boot up your Arduino board, plug the cable's pins into the Arduino pins and then the last step is you can plug the 30-pin connector into the iOS device.

If you just plug it in and expect it to work without paying attention to this process - it most likely won't work. It's a bit buggy at first, but once you get it working in this order it's a great product! I hope this helps others because I couldn't find anything that explained this process and I had to figure it out from trial and error.

I would also recommend Alasdair Allan's book:



I'm having the same problem with my C2-TTL cable. I'm just trying to go through Alasdair Allan's book that you mentioned. I copied the programs line for line. The Arduino program works when I open the serial monitor on my computer, but it can't get it to establish a serial connection through the cable to my phone. I tried booting the Arduino, connecting the rx tx and ground to it and then connecting the cable to my phone. I wait a few seconds and then I open up the app on my phone, sometimes it crashes, sometimes it doesn't. When it doesn't, it doesn't make the connection, the tx light on the Arduino doesn't blink like it did when using the serial monitor.

Any suggestions? Thanks for the help.