CarlinKit 5.0 (2air) Wireless Carplay Adapter Full Review

I have actively been using the CarlinKit 2.0 Wireless CarPlay Adapter for about two years already. While it certainly is a useful gadget, upgrading the car’s stereo to support Wireless CarPlay, it is not without one or the other quirk. Now that newer versions of the adapter have been released which are advertised as being faster and more reliable, I thought I would give the CarlinKit 5.0 2-in-1 Adapter (CPC200-2air) a shot, adding the ability to hook my wife’s Android phone up to the car’s stereo wirelessly which comes in handy as my wife typically hosts the kids’ playbooks and stuff on her phone whereas I am responsible for some good music.

⭐This write-up may go beyond the scope of a conventional review, also giving advice on how to squeeze the most out of CarlinKit’s wireless adapters.

Testing Conditions:

• CarlinKit 5.0 (2air) 2-in-1 Adapter
  FW 2023.08.14.1923
• SEAT Leon Sportstourer FR (2019)
  SEAT NAVI SYSTEM (MIB2 STD2Nav / MST2_EU_SE_ZR_P0516T)
• iPhone 13 Pro
  iOS 16.6
• Xiaomi Redmi Note 11 Pro 5G
  Snapdragon 695, Wi-Fi 5 1×1 (433 mbps), Android 13 (MIUI 14), Android Auto 10.2.633224-release

Review History: [2023-09-07] initial publication (FW 2023.08.14.1923)

Specs

This review is no teardown either, mainly focussing on the user experience. Wireless CarPlay through the CarlinKit 5.0 does not feel too different compared to previous generations of the adapter which are known to be based on the NXP/Freescale i.MX 6 automotive platform.

Power consumption measured at around 1.2 W while navigating and playing music, being about 30% more than the 0.9 W of the 2.0 however. The discrepancy may very well be due to different Wi-Fi modules/modes being used.

There are certainly faster booting wireless adapters out there. It didn’t come as a surprise that boot times even slightly increased with the CarlinKit 5.0. The reason most probably being that with the adapter performing a straight passthrough of either CarPlay or Android Auto, it has to know the platform of the phone to be connected before the negotiation process with the head unit can start.

Average signal strength has been measured on channel #36 over a period of 5 minutes at a distance of 0.5 m. CarlinKit 4.0 and 5.0 both have vastly improved RF signal characteristics compared to 2.0 which will certainly help holding onto the signal in heavy interference scenarios. The Wi-Fi channel can finally be adjusted to the advertised 5.8 GHz (UNII-3) frequency band which may be less crowded than the lower 5 GHz frequencies. So in case you are suffering from connection reliability issues in always the same spots (e.g. around densely populated urban areas), you may want to try switching the Wi-Fi channel. Keep in mind that a lesser transmit power may be used for UNII-3 frequencies, therefore being more easily interfered with. With the car acting as a faraday cage and the adapter’s improved signal characteristics, it probably won’t suffer from outside interference too much, with interference typically also being rather transient.

CarlinKit 4.0 and 5.0 effectively support Wi-Fi 5 (802.11ac) with link speeds up to 866 mbps (with 2×2 MIMO on 80 MHz wide channels) as per Apple’s recommendations, also enabling the WMM Quality of Service mechanism for improved VoIP latency and input reaction times. I wonder whether it is really all that wise to use an 80 MHz wide channel. Considering that CarlinKit adapters are USB 2.0 Hi-Speed only, I don’t think that a ~800 mbps wireless link will have a considerable impact on the application’s performance. Wireless CarPlay is in fact designed to work on a 20 MHz channel in the 2.4 GHz band. CarPlay and Android Auto both use a peer-to-peer connection, not transferring a hell of a lot of data (a maximum of 10-11 mbps for Wireless CarPlay). A 20 MHz channel on the 5 GHz band is much less prone to interference while at the same time not messing with the application’s performance which can actually be proven by switching to channel #165 which effectively limits bandwidth to a quarter (~200 mbps). Maybe a 40 MHz channel would be a good compromise between minimizing interference and maximizing throughput with link speeds of up to ~400 mbps, also being in the ballpark of USB 2.0 Hi-Speed. It has to be considered though that for phones not supporting multiple spatial streams (MIMO), maximum link speed will be limited to ~200 mbps on a 40 MHz channel.

CarlinKit adapters still use the hard-coded and well-known 12345678 passphrase, enabling another non-paired phone to manually connect to the adapter and change settings or initiate a firmware update via web interface. The adapter should in my opinion generate a random passphrase for Wireless CarPlay and Android Auto in order to prevent manual connections which is a non-requirement anyway. The idea probably is to still have access to the adapter in case the Wireless CarPlay or Android Auto connection fails in order to be able to tweak compatibility settings or update the firmware.

⭐With respect to security it is important to point out that no personal data from your phone is transferred via CarPlay or Android Auto. So no concerns in that regard when using a CarlinKit adapter.

The USB-A port of the adapter is not advertised as being a charging or wired CarPlay/Android Auto passthrough port anymore but is only meant to be used as an emergency backup for flashing firmware via pen drive in case OTA updating isn’t possible due to broken firmware. The current output of the USB-A port on all CarlinKit wireless adapters is limited to 500 mA anyway, resulting in a maximum power output of only 2.5 W which won’t make a connected phone charge at a reasonable speed.

⭐I strongly advise installing a MagSafe/Qi wireless or USB Quick Charge/USB-C PD charger via 12 V on-board (cigarette lighter) socket, providing 15 W and more for faster charging.

Design & Build Quality

The 5.0 2air features yet another major industrial design upgrade, probably being the most modern one among CarlinKit’s wireless adapters due to its more edgy nature with the LED nicely sitting behind a CarlinKit logo. At least to me it is the most visually pleasing one with its matte finish. Many people may hide the adapter behind the car’s fittings though. So they couldn’t care less about its look.

What’s new from a functional point of view are the holes at the side for improved airflow in order to keep temperatures down inside the housing, supposedly improving reliability on a hot summer day. Another useful change is that the USB-C plug is not as deep anymore, boosting cable compatibility.

Plug & Play

Unlike other CarlinKit wireless adapters, the 5.0 2air does not display an initial boot menu anymore after plugging it into the car’s USB port. This does not make installation any more complicated though. It is no harder than pairing the phone to the adapter’s AutoKit-XXX Bluetooth. Wi-Fi credentials are exchanged transparently over which connections are magically established whenever the paired phone gets close to the running car.

⭐Keep in mind that for any CarlinKit adapter to work, the car has to at least support wired CarPlay or Android Auto via USB.

It typically takes no longer than 20 seconds after turning the ignition switch until music from the phone starts playing over the car’s speaker system. Mileage may vary depending on the used car and/or head unit. In case of my Leon Sportstourer, its factory-fitted MIB2 infotainment system is already starting up with USB ports being powered when unlocking the car.

⭐Connecting to Android Auto is a bit hit or miss, typically taking a second attempt, also requiring user input each time the CarlinKit 5.0 boots into the Android ecosystem in order to choose between Android Auto and MirrorLink which should only occur once at the very first connection, remembering the selection made.

Multi-Phone Support

The CarlinKit 5.0 allows multiple phones to be paired. There is no dedicated facility to select or on-the-fly switch between phones across the two supported platforms though. Here is a best practice for cross-platform phone switching that I could come up with while actively using my wife’s Android and my iPhone…

⭐With the adapter using default settings, it automatically attempts to connect to the last used phone. If that one isn’t reachable, the adapter will try to connect to the other one. In order to get from one phone to the other, disabling Bluetooth and Wi-Fi on the currently active one will cause a disconnect with the adapter automatically connecting to the other. Enabling Background mode inside the adapter’s settings will hide its half-baked UI altogether.

Wireless CarPlay

Human Machine Interface

Navigating the CarPlay interface via touchscreen over wireless does not feel much different compared to wired. This clearly indicates that the concept indeed works with an only barely noticeable increase in lagging. Any input inaccuracies may also be due to the mediocre head unit with its matte touchscreen built into my car. Multi-touch gestures are not supported by the MIB2 for CarPlay as the specification officially only supports single-touch.

⭐As for pinch-to-zoom inside maps apps (like Apple or Google Maps) there is however also a one-finger-gesture to achieve that.

The iPhone properly detects through the adapter that CarPlay is controlled via a touchscreen rather than a rotary knob or trackpad. So the iPhone does not erroneously focus on some menu item. Dark and light modes are switched automatically based on whether the car's lights are on or off. Also metadata like phone call information, route guidance and the currently playing audio track is properly being displayed via the instrument cluster. So all information between head unit and phone seems to properly pass through the adapter.

Steering wheel controls for volume and track skipping (previous/next) work fine as well. Unfortunately, seeking (fast-forwarding/rewinding) the currently playing audio track by long-pressing the skip (previous/next) buttons is not supported through the adapter. This can however still be achieved via the CarPlay interface’s soft buttons.

Siri is supported and can be engaged by long-pressing the voice control button on the steering wheel. Voice activation via “Hey Siri” also works, which I can only test through the iPhone’s mic as my car lacks an always-on mic.

Media Playback

While Apple specifies uncompressed LPCM audio for wired CarPlay, Wireless CarPlay uses the compressed and lossy AAC-LC format for media audio which the adapter therefore needs to decode. There is no audible quality degradation which may however depend on the music service and used audio codec/bitrate combination. For services using AAC (e.g. Apple Music), wired vs. Wireless CarPlay shouldn’t make any difference. It typically doesn’t matter whether the iPhone or the adapter decodes the audio stream. Main goal of the adapter seems to be preserving the original sound quality with the output being rather neutral which can be optimized via equalizer of the in-car amplifier.

Spotify uses a pretty transparent 320 kbps Vorbis in its highest quality preset. Transcoding that to 256 kbps AAC-LC shouldn’t do too much harm either. Low bitrate MP3 internet radio stations will probably suffer the most. Those however suffer anyway, still sporting more dynamics than good old AM/FM though. Keep in mind that compared to a studio, a car is a rather noisy environment. Asking for some lossless or Hi-Res audio would therefore probably be too much.

⭐I don’t recommend using any in-app equalizer (e.g. inside Spotify). That’s the job of the last link in the audio playback chain in order to tune audio for all available music sources in the car.

Transitioning between and mixing multiple audio sources works flawlessly, for example engaging Siri or the navigation app giving directions while listening to music, either via iPhone/CarPlay app (e.g. Apple Music or Spotify) or the head unit’s CD/radio tuner. The adapter properly handles the different types of audio (music, speech/Siri, phone call, ringtone), enabling the head unit to store separate volume levels for all of them. So you can for example turn up your music while still getting directions at a reasonable volume.

⭐There is one advertised feature of the CarlinKit 5.0 which I couldn’t verify working. The LED is supposed to act as an ambient light, synchronizing its color to the average background color of the album artwork displayed inside the Apple Music app. The LED kept flashing green in my case, indicating a proper CarPlay connection. I personally find a flashing or color changing light rather disturbing.

Audio Delay

The adapter-side audio decoding however seems to have one major drawback. It by default uses a 1000 ms big buffer in order to compensate for transmission fluctuations over Wi-Fi, resulting in a total audio lag of >2 seconds.

⭐The buffer’s size (a.k.a. Media Delay) can be configured via the adapter's web interface. It can in many cases reliably be set as low as 300 ms, still resulting in flawless audio most of the time, causing an effective lag of around ~1.5 seconds.

So how does this audio lag manifest itself? When for example skipping through songs, it takes the mentioned amount of time until audio reflects the change. 1.5s doesn’t sound like much but it is very noticeable compared to the almost instant wired CarPlay. It is certainly above Apple's latency requirements for media audio. What probably has to be added is that turn-by-turn instructions still arrive perfectly in time.

The CD/DVD Category setting does not have an impact on audio lagging and reliability. CarPlay supports 16-bit audio at 44.1 and 48 kHz. In case the CD option is selected, only the first sample rate is advertised with the iPhone applying an appropriate conversion for other sample rates.

Telephony

Making phone calls through the CarlinKit 5.0 adapter works in principle. There is some talking over each other every now and then which however also happens with the factory-fitted wired CarPlay. Some factory-fitted head units with integrated Wireless CarPlay, some of which only operate in the low bandwidth and interference-prone 2.4 GHz frequency band, are said to be lagging so badly that making phone calls isn’t feasible at all.

In order to assess the phone call behavior, I called an echo test number and measured the round-trip time (RTT or two-way delay). With no CarPlay involved at all, RTT measured at ~300 ms using an iPhone 13 Pro. With wired CarPlay of the MIB2 in between, latency increased to ~600 ms. The CarlinKit 5.0 adapter added another ~200 ms on top, resulting in a total RTT of ~800 ms. That's quite a lot, however being in the ballpark of the ITU’s proclaimed acceptable one-way delay of up to 400 ms for conversational audio (extrapolated to 800 ms for two-way communication). Recommendation however is 150 ms (300 ms) and below.

The higher delay may probably be more of a systemic than an adapter specific problem. To get from phone to head unit and vice versa, data has to travel over several bus interfaces with format conversions along the way as Wireless CarPlay uses compressed but latency optimized audio formats for speech (either Opus or AAC-ELD). I tried to assess latency of the Wi-Fi part alone by issuing the ping command from the iPhone to the adapter which measured in at 3-5 ms without massive outliers.

GPS Navigation

A common problem with Wireless CarPlay is that the iPhone may be placed in a location without any GPS satellite visibility, e.g. in the pocket, a bag or a dedicated wireless charging cradle. Apple therefore mandates that location information of an in-car GPS antenna gets passed on to the iPhone via CarPlay enabled head unit. The MIB2 of my Leon Sportstourer comes with navigation built in, therefore featuring a GPS antenna.

I tested turn-by-turn navigation with the iPhone in my pocket and the glove box, using some of the most popular CarPlay-enabled online and offline navigation apps available such as Apple Maps, Google Maps, Waze, TomTom GO or Sygic GPS Navigation. Location information of the in-car GPS antenna passes through the CarlinKit 5.0 adapter perfectly fine, helping to improve accuracy and also to preserve battery life of the connected phone.

Wireless Android Auto

Unlike the CarlinKit 4.0 which converts Wireless Android Auto to CarPlay, therefore not requiring an Android Auto compatible head unit, the CarlinKit 5.0 performs a straight passthrough from Wireless to wired Android Auto. This certainly has a positive impact on responsiveness, also enabling some Android Auto exclusive features of the MIB2 such as multi-touch gestures like pinch-to-zoom inside maps apps.

There is also a difference between CarlinKit 4.0 and CarlinKit 5.0 with respect to how visuals are rendered. With the CarlinKit 5.0, Android’s car projection uses a touch-friendly 160 dpi as proposed by the MIB2.

CarlinKit 4.0 @ 120 dpi

The visually more pleasing rendering via CarlinKit 4.0 adapter at 120 dpi with more real estate being displayed comes at a cost though with smaller icons being harder to hit, text harder to read and also an increased input lag. The DPI can however be adjusted to everybody’s liking which is a big plus of the adapter. The CarlinKit 5.0 still is the clear winner in terms of responsiveness though.

Wired and Wireless Android Auto both use the Bluetooth Hands-Free Profile (HFP) for making phone calls. The brilliant thing about the CarlinKit 5.0 implementation is that the HFP connection is established directly to the car’s Bluetooth rather than the adapter’s, resulting in less lagging compared to Wireless CarPlay. In fact, RTT measured at around 500 ms which is even less than wired CarPlay. Interestingly, Wireless Android Auto also suffers less from media playback lagging compared to Wireless CarPlay despite not taking any shortcuts like phone calls.

It has to be concluded that with the CarlinKit 5.0, Android Auto has the edge over CarPlay even when being used with a mid-range Android phone with limited Wi-Fi capabilities.

Web Interface & OTA Updating

CarlinKit adapters still enjoy lively support with CarlinKit constantly fixing bugs, improving compatibility and performance. A recent upgrade introduced major web interface design and functionality changes which even my “old” 2.0 received. The web interface can be reached via web browser on the connected phone (URL=http://192.168.50.2).

⭐In case of Android, the Wi-Fi access point of the adapter has to explicitly be connected to via Android Wi-Fi settings using the 12345678 passphrase. Since some phones do not properly connect to a Wi-Fi network which lacks internet connectivity, it may be necessary to sideload the AutoKitools app in order to be able to access the adapter’s web interface. The app didn’t receive much love but it does what it is supposed to do.

The front page of the web interface now displays some in-depth information about the status of the adapter’s hardware which may help with debugging in case of problems. Geeks among us certainly celebrate this new feature.

With newer versions of the firmware, it is possible to customize the logo of the shortcut which takes you back to the car’s infotainment menu. Wi-Fi and Bluetooth network names can also be customized.

Then there are a handful of configuration switches which are meant to tweak the experience or work around compatibility issues with integrations of certain car and head unit manufacturers. Unfortunately some of the used terms are either poorly translated or not very intuitively chosen (e.g. Category which is more like an Audio Compatibility Mode).

The Wi-Fi channel can be changed in case of constant interference problems. As for Wi-Fi security, it would probably make sense to also be able to change the passphrase. This would fix the security issue of the known hard-coded passphrase while at the same time preserving the ability to manually connect to the adapter in case of problems.

The OTA updating mechanism is quite straight-forward. Just visit the web interface’s Help page and press Check Update. You will be prompted to install in case an update is available. Beware that firmware images are downloaded via your phone’s mobile plan. Those files are rather small though, typically being around 10 MB.

⭐Better leave the car engine running while updating the firmware in order to prevent the USB from entering some power saving state or being switched off altogether. Also do not plug your phone (nor any other device) into the adapter’s USB-A port while updating in order to prevent potential disruption, either from power or data side.

⭐In case you manually connect to the adapter’s access point via 12345678 passphrase, make sure to ignore/forget the network in the phone’s Wi-Fi settings when the web interface is not needed anymore in order to prevent future autonomous connections as this may cause interruptions on an active CarPlay or Android Auto session in a multi-phone scenario. Don’t mess with the Auto-Join setting though as disabling it may also have a negative impact on CarPlay/Android Auto connectivity.

Verdict

Judging from some older rather devastating reviews that I stumbled across, it looks like the CarlinKit adapters have come a long way and matured quite a bit over time. I pretty much prefer this breed of Wireless CarPlay and/or Android Auto adapters.

There is no guarantee for an Apple-like carefree experience which is mostly due to the fact that the CarlinKit adapters are based on reverse engineered CarPlay and Android Auto protocol implementations, potentially suffering from compatibility issues with certain cars or head units. Therefore a Made for iPhone logo is nowhere to be found. For cars already supporting wired Android Auto, the CarlinKit 5.0 adapter is certainly the better option over the CarlinKit 4.0, performing a straight passthrough of wireless to wired Android Auto rather than a cross-conversion to Apple CarPlay.

With my setup, the experience came close to perfection with both, Wireless CarPlay and Android Auto. In fact the experience has gotten so good that you will never want to go wired again. In order for the Stability and Overall categories to receive a full five stars, CarlinKit still has to overcome some rare disconnect scenarios which in my opinion are not necessarily related to Wi-Fi interference.

Here is a final rundown of the yays and nays…

 

Thanks: Guest written by Daniel

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