I have just finished drawing up a plan of my ICE system on a Post-in note and my god is it complicated. I thought I'd share this with people on here as what I have come up with may be of great use to those of you who have Sat Nav and wish to retain it but also have a decent ICE system.
Firstly - I have an NCDR-1100 Siemens headunit - this is the optional Vauxhall Sat Nav in the Astra Coupes. I also have the colour screen.
I have now bought a top end Alpine CDA9835R headunit. The key to using this head unit is the Ai-Net input port.
I have bought an Alpine KCA121 cable, which allows you to plug an RCA into the Ai-Net port and select it via the headunit as a source. I have also bought an Alpine NVE-410C; this is an Ai-Net interrupt box, which allows you to select a second RCA input via a switching lead.
I also have on order a Nokia CK-7W advanced Bluetooth hands-free phone kit. This kit has an aux. output, which can easily be converted to an RCA via a standard jack to RCA cable.
Also on order is a Stinger Saloc - which is an adjustable speaker level to RCA converter.
I already have a DLS Ultimate A5 3 channel amp, 2x Boston 12.5LF 12" subs, Shark power supply cap, 6.5" MBQuart components for the front and 4" MBQuart components for the rear.
Right - you are possibly confused a bit now, but this is how it goes together. The Sat Nav unit will be connected to the Stinger high to low level converter and then connected to the Alpine KCA121 RCA to Ai-Net lead which will then go into the Ai-Net input on the KCA-410C which then plugs into the Ai-Net port on the Alpine Headunit (simple right?).
The Nokia car kit aux. output is connected to a jack to RCA lead and then into the RCA input on the KCA-410C. The interrupt on off the phone kit it plugged into this too, as well as into the interrupt on the Alpine headunit and the Sat Nav system (if possible).
The subs and the front speakers are powered off the DLS amp and the rear speakers off the Alpine headunit.
Now - what this does is allows the Say Nav unit to be selected as a source unit via the Alpine headunit. This will route all sound through the Alpine and then to the amp and then to the speakers. The phone kit will create an interrupt when in use and will feed the sound into the Alpine headunit via a second source which is automatically selected with the interrupt cable.
This also means that not only can you use the Sat Nav through the main speakers, but also the standard tuner and CD and CD changer - which is controlled via the steering wheel with info displayed on the colour screen.
This also allows you to adjust the volume of the car phone kit via the Alpine headunit. Alpine head-units also allow different EQ and other sound settings for each input - meaning you can set-up the phone kit to have less bass if required.
Now this is all theory at the moment. I'll have all the bits within the next few days and will fit it all over Christmas. I'll let you know how I get on - assuming I don't get tangled in the wires and stuck in the car forever!
Oh - to confuse things further, I'll later be adding an Ai-Net iPod controller, which give full control and display of track names and lists via the Alpine headunit.