This accessory is not supported by iphone

I have the following iPhone accessories:-

Phillips DC390/05 Alarm Clock

• Pure Twilight Alarm clock using iDock i-10
• Sony Hifi (CMT-CX5BiP)

I used to have an iPhone 4 32GB on the latest IOS 6.1.2 and it worked perfectly with these devices. I dropped it and smashed it (for the second time) and decided to buy a 2nd hand iPhone 4s 64GB. It arrived and I performed an iPhone restore from iTunes. Everything is great with the new iPhone 4s and it is in perfect working order with no signs of any damage/dirt to the dock connector. But when I try and use it on the Phillips Alarm Clock or the Pure iDock I get the "This Accessory is not supported by iPhone" error and I cannot use them as speaker docks, although it charges fine and work perfectly via the Sony hifi. My iPad, iPhone Touch, iPod classic work fine with all three devices.

When I first got the phone and before I had set it up I charged it on the Philips Alarm clock, I then inserted the SIM card, run the setup wizard to connect to 02 and activate before hooking it up to iTunes and running the restore proceess. After I this had completed the restore, I restarted and then synchronised with iTunes again, I tried to play some music through the speakers but no sound would play, the Airplay option showed only my Apple TV devices and iDock connector as output options. I performed another restart and then it played music happily through the speaker fine. But the problem began with I tried to play music through my Philips alarm clock and got the "This Accessory is not supported by iPhone" error, again the phone happily charged on the dock fine.

I've tried:-

• restarting the phone
• Switching off the home screen and connecting to the dock
• Turning the iPhone off and connecting to the dock and turning on
• Reset all settings (Preserving data)

The only thing I can think of is that the Philips and Pure Alarm clocks do extra functionality than just a speaker dock. The Philips synchronises its clock with the iPhone and the Pure dock has an App which allows you to play Internet radio through the dock. Could it be a hardware error or software bug? If its hardware I can send it back as I have a 30 day warranty but rather not go through the hassle if its a software glitch that I can fix.