Thread: Using TMC in Garmin nuvi for free

Originally Posted by itzbinnice

Interesting scenario I’d like to share.
I have a newly acquired Nuvi 670, seems like the previous owner never even attached the GTM20 transmitter, the unit and accessories look brand new.
I previously had a Nuvi 660 that broke so I still had all the accessories from that unit and have been using the 660’s transmitter with the expired subscription on the newly acquired 670.

As an experiment, I hooked the old 660’s transmitter to the 670, and under traffic it showed subscription had expired.
I entered the generated TTL unlock codes for both North America (28992) and Canada (31808).
The unit took both codes successfully. When I went to check on the status it indicated two subscriptions, one lifetime and the second being the expired one which now had a date of October 2008. I plugged it in the car to see if it worked but it indicated it was waiting for information from satellites. My satellite icon showed all bars at full strength. Sat there for awhile and nothing changed, so being impatient I disconnected it.

Now for part 2 of the experiment.
I disconnected the old 660,s GTM20 and connected the new one that came with the 670. I turned unit on and a sign pops up loading software.
Looks like the previous owner never even connected it since I got a message that indicated I now have 3 months free traffic subscription.

I was nervous about entering new codes but I went ahead and generated new TTL codes for this transmitter. I entered the codes into the 670 and it accepted them and now displayed Lifetime Subscription but did not show the previous 3 month free subscription. I found it odd that the first GMT20 from the 660 showed both subscriptions, and the newly activated 670 only showed the Lifetime Subscription. Doesn’t matter, I was just happy that it works.
I won't be connecting the old 660's transmiter agian in fear of corrupting any software on the Nuvi.

I am wondering if these subscriptions are added to the GarmineDevice.xml file, or are they transferred to a chip on the GMT20 receiver.

I believe the codes are sent to the GTM20....because I can use my GTM20 on any of my 660's and it works fine and shows the same subscriptions on it

I have another question I hope I can get an answer to.

I just bought a brand new Nuvi 1350T, it came with GTM 25 and has lifetime subscription to Navteq, I'm using CN North America 2011.40 map.
I keep getting advertisement ads which are annoying. I see on the Garmin site they have Premium Lifetime Navteq Subscriptions and Premium Total Traffic Network.
I assume the Navteq is advertisement free. (Total Traffic Network has no advertisements)

My first question is, using the procedure that catymag outlined in post # 1, does this generate a unlock code for Navteq Premium Subscriptions or one that has advertisements?
Also, if this is Premium Subscription and I add the unlock codes for Canada & U.S., will this overwrite the free based original one or add another subscription that may cause a conflict with the FREE one installed.

I did follow catymags’s instructions and was able to add a subscription for Total Traffic Network, the GTM 25 accepted and I never lost it like others reported. Now I have both networks recognized but I want to get rid of the free ad based one that came with the receiver.

I do believe these are permanent records sent to the GTM 25 and cannot be altered.
I just need to know if by adding unlock codes for the Navteq Network will this overwrite the original subscription or add another one and possibly cause a conflict.

Sorry for making this post longer than should be, I only want to provide as much information as I can.