Thursday, January 12, 2012

GSM or CDMA? Why YMMV with Garmin's Smartphone Link

I'm a couple days into the use of Garmin's Smartphone Link with my Nuvi 3490LMT.  

Today my 2 hour drive included a 1 hour conference call.  The Nuvi bluetooth provided for an easy, safe method of carrying on a conference call for that length of time.  I really don't need to carrier my Motorola T505 bluetooth speakerphone anymore.  One less device in my bag!

Bored, and 15 minutes into the call I realized that I no longer had traffic content.  Duh!  I have a CDMA phone.  And of course we all know from the AT&T iPhone commercials that only AT&T (GSM) allows you to enjoy simultaneous voice and data.  Using Verizon? Sprint? Another regional carrier using CDMA technology? Nope.  Sorry. You can have voice or data, but not both at the same time on the 3G network.

When Garmin fixes the Smartphone Link and GMT-60 issues so that Smartphone Link Live Traffic can be used while plugged into the GMT-60 I hope that Garmin thinks through how the Smartphone App and the GMT-60 should work for CDMA customers.

Without any proof to back up this statement, I am going to go out on a limb and suggest that today's typical customer of a $400 PND and the Smartphone Link app is a tech-savvy road warrior.  And being one of those likely means phone calls while on the road are a regular occurrence.

Based on what we know today, the HD Radio Traffic from the GMT-60 appears to take a back seat to Smartphone Link Live Traffic.  This means that it appears that if Smartphone Link is active and connected to your phone, the Nuvi uses Live Traffic only and not HD Traffic.

Take a phone call on a CDMA network though, and you've got a problem.  While your Smartphone Link app and Nuvi are still bluetooth connected during a voice call, your phone isn't receiving data from your CDMA cellular carrier so your Nuvi isn't receiving any traffic content from your phone.  Take a call on a long stretch of rural Interstate - no problem.  Take a call during the last 15 miles into downtown Chicago and you've got a problem!

If your using Smartphone Link, your Nuvi has this perfectly good GTM-60 HD Radio Traffic receiver sitting around doing nothing but providing power - it should be able to provide traffic content to your Nuvi in the event of a loss of content from the Smartphone Link app.

It is my hope that Garmin improves the detection and switchover of traffic sources between Smartphone Link Live Traffic and GTM-60 HD Radio traffic in an intelligent way.  Clearly the Nuvi knows that the phone is in voice call mode because the Nuvi is capable of handling the call.  I think that Garmin should include logic where the Nuvi automatically switches to the GTM-60 HD Traffic receiver when the phone is in a voice call state.  Garmin could include a menu setting that asks the customer what cellular carrier they are using (or detect it somehow through the Smartphone Link app - is that possible?).  For GSM carriers - no switchover is necessary.  For CDMA carriers the switchover could be implemented.

With both the GTM-60 and Smartphone Link at the Nuvi's disposal, I hope Garmin doesn't settle for a complete loss of traffic content during a CDMA voice call as being an acceptable operating scenario just because one of two available sources isn't available any more.  Switch us to the other source Garmin - please!