TMC Information

[mikealder]

TMC (Traffic Message Channel)

There are two different methods for getting TMC data to work with your device, GPRS or RDS-TMC. The RDS-TMC only works with the TomTom Go-510, 710 and 910.

GPRS Based

The GPRS system uses a Bluetooth link to connect to your mobile phone, once connected and set-up the device can access a server to download the traffic data. In order to use this service your mobile phone must have full internet connectivity (WAP access is not sufficient).

If your phone is on contract you may still have to contact your phone service provider to have the required privileges enabled. Note phones on the “3” network will not work with the TomTom server, this is due to how network 3 lock down the internet access to sites within its own umbrella, if it’s a 3 network phone – forget it, or get a different sim card.

If you use a Pay As You Go service for your mobile phone then your options are somewhat limited, you should check with the phone service provider if it is possible to access full internet, and check it works before committing to the TomTom Traffic subscription.

Irrespective of phone type, payment method etc please check the associated costs for using GPRS with your mobile phone, the cheapest way to use GPRS is with a service bolt on that gives you so many MB per month for a flat rate cost. Please do check this out, certain phone companies charge ludicrously high charges – you don’t want to receive a huge bill.

On the topic of costs, it is also worth mentioning the file size of a typical days download. My device was set to update every 10 minutes (which to be honest is probably too often, 15 or 20 minutes is a more realistic figure). After driving six hours the device had downloaded 322Kb of data, if possible monitor your GPRS traffic on the phone SPB GRPS Monitor is great for those using PDA based phones.

The data that is downloaded is country specific so you don’t receive traffic information for the whole of Europe, you do get all the traffic information for the country unlike the RDS-TMC (see later).

RDS TMC

This method involves a radio receiver that connects to the TomTom Go-x10 devices mount, it uses the same connection point as an Ipod cable connect, so you can only use RDS or Ipod, not both at the same time.

Traffic information is transmitted over the normal FM radio frequencies, the actual channels are those employed by Classic FM, please note no other radio station is currently used to relay the TMC data.

The lead from the TMC unit to the Go device is actually the aerial, please don’t coil this up – it needs to be fully deployed to maximise the reception of the radio signals, which in the UK are relatively low power if compared to those on mainland Europe.
Also don’t try extending the cable, it contains four individual wires, which do not lend themselves to being cut, stripped and spliced/ soldered to longer wiring, think about the warranty – it can’t be sent back if you have butchered it.

The actual data received by the device is regional – you do not get the full country traffic data using the RDS-TMC. In practice I don’t find this a problem as you move around the country the actual transmitter you receive data from will change. With that change is also an alteration to the data transmitted, typically in Blackpool I can see traffic information across to the East coast, as far South as Birmingham and North up to Carlisle.

Your unit will receive new regional data long before you get to the edge of the current region you are actually in.

With the arrival of software version 6,522 (7709) a few new additions to the RDS-TMC software have been made available.

The TMC indicator on the navigation screen (top right) will only be coloured green if the unit is tuned to Classic FM, if tuning is in progress the TMC indicator will be amber coloured and appear to be rotating.







To assist the device to locate the Classic FM signal you have the option to manually tune the device to your local frequency, tap the screen in the area where traffic delays are displayed (right hand edge of the screen).
The Tune RDS-TMC icon should be available top right of the display, when the TomTom is first powered up the Tune icon is not always available for selection if greyed out try selecting again after a short wait.
Also you must have a route planned to be able to access the page the Tune Icon is displayed on.



Enter the frequency for your local Classic FM transmitter, this information can be found in your local paper, or try tuning the car radio until it finds Classic FM, then input the values and press done.



The unit has now found the Classic FM channel, which is displayed in the lower left corner of the screen, in certain areas the unit will not find a sufficiently strong radio signal in which case it will revert back to scanning the frequency band.

The small green arrow rotating above the image of the car (lower left) indicates an update is in progress.



Once the device has obtained traffic data the indicator lower left turns to a solid green disk, adjacent to this, the frequency and radio station name is also displayed.

The other icons are now selectable, prior to data being available they were greyed out, (note this image was taken using a Go-910 The Read aloud traffic info is only going to work with a 910 device as it is dependent upon the Text To Speech system).



With the unit now receiving TMC data you get the following display in the navigation screen, not much in the way of options to re-route to avoid this location though – Dartford Toll Bridge.



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How to find the correct frequency for the RDS-TMC relative to current position.

In order to know the correct frequency as you travel around the UK it is possible to use a custom POI file that contains the location, name, power level and frequency of all the transmitters.

Once installed to the device go to Browse Map and tap the Find button. Select POI/ POI near you select the TMC POI in the list and the unit will return the information you need.

Note the transmitters power level is included in brackets this value is in KW the higher the figure the longer the effective range of that mast.

If the first frequency listed fails to work it is also worth trying the others nearest your position.




If anyone wants the TMC POI file please use my e-mail button below and I will reply with the files attached (they are small files).

Click HERE to return to the FAQ page.

[Fraserp]

Mike,
Many thanks for this update.

So, if I understand correctly you are\ may be required to manually 'tune' it to Classic FM?
Having to do that repeatedly on a long journey is a non starter. Surely TT know the frequencies?
IMHO, ANY requirement to tweak the unit by manually tuning it renders it 'not fit for purpose'.
Also, does anyone know what is the situation in Europe? Is any manual tuning required on the continent?
Thanks
_________________
Fraserp
TomTom 910, 920
GPSmap 60CSx
SatMap
SatSki

[mikealder]

Fraserp, the unit is quite capable of auto tuning, but when in poor reception areas you now have the option to manually inform the device which frequency to use. This can in practice speed up signal acquisition.
I have never tried the TMC unit in Europe, but it is widely known the transmission power is higher in Europe than the UK, so I would expect better reception over there - Mike

[Fraserp]

I must be being a bit dumb here (not for the first time).

If you manually tune it, surely it then locks to that signal. What if you then leave that area? Say on a long journey. Do you have to go through that proces again, or does it 'automatically' switch?
_________________
Fraserp
TomTom 910, 920
GPSmap 60CSx
SatMap
SatSki

[mikealder]

Once the TMC unit drops the signal it resumes scanning the FM band until it finds another Classic FM transmitter, so it is automatic - also if your entered frequency produces no data the unit will resume scanning the entire band fairly quickly.
I have just used it on a long 660 mile round trip, and being able to input the frequency manually was a major plus point, the device locked on to the entered frequency most of the times I entered a manual tune, other times it found the correct frequecy and worked automatically without intervention - IMHO its better than before, but still not as reliable as the GPRS method of obtaining TMC data to the unit - Mike

[mark1968]

I work as a HGV driver and cover most of the country. TomTom has shown other stations transmitting data for example Radio 1, and Heart FM.
_________________
Regards,
Mark
Tomtom GO 530, iPhone 3GS with TomTom, iGo and CoPilot

[mikealder]

Mark, Try it with the new software and see if you actually get a green light with any station other than Classic FM, I would be most interested to know which station and where.
What you have probably observed is the unit having stored RDS-TMC data, re-scanning looking for a signal - it then showed a green light when locked to the wrong channel, the new software version cannot do this, if its not Classic FM then the top right disk is rotational amber.
If any traffic information is still stored by the unit the delays etc will stay displayed after the Classic FM signal has been dropped (for a short time period), which used to lead people to the conclusion that other stations were transmitting the data - Mike

[Fraserp]

Mike wrote

[Martin4Jay]

[mikealder]

The files are standard POI files both the ov2 (which contains the locations) and the BMP (which contains the icon) go in your map folder, on the 910 it is named Western_and_Central_Europe - this is the same folder you would place the speed camera POI files - Mike

[SpeedCam]

It won't be long before we see these TMC receivers in the 99p discount rubbish buckets of Dixons & PCWorld, then it maybe worth buying one. :o

[Martin4Jay]

Many thanks Mike. :D
Cheers

[Madmouse]

might sound a bit daft...i've latest software on a tomtom 510 with tmc i'm getting all icons mentioned as well as occasionally an icon I don't recognise..it's a car with animated green arrow going across above...is this meaning data being received?

[mikealder]

Thats actually good news, at least the device is trying to receive information and must be tuned to the correct frequency - give it a few minutes and you should be able to see traffic information on the traffic map (these are displayed as small red icons, tap one to get further details about the incident) - you might need to zoom out on the traffic map to find the icons though, try zooming out to a county level rather than country - Mike

[Martin4Jay]

Can I request that all members put there nearest destination in there profile as it would give others who may be thinking in buying one an idea in the reception with the TMC .
Please move it if it's in the place.
Cheers