If you have a unit like the nüvi 3790 or similar you can look in "[GPS drive]:\.System\TrafficProvider.xml".
Here's an example with extract of 2 entries from TMC providers in France:
V-Trafic (FR):Code:<country name="France" cc="15" ecc="225" fmTuningGrid="World">
...
...
<provider>
<providerName>V-Trafic (FR)</providerName>
<pay>true</pay>
<tuning ltn="30" sid="62"/>
<tuning ltn="32" sid="62"/>
</provider>
<provider>
<providerName>Via-Michelin (FR)</providerName>
<providerCopyright>Copyright-RDS/TMC Traffic Information Services France-ViaMichelin</providerCopyright>
<pay>true</pay>
<tuning ltn="29" sid="58"/>
<tuning ltn="32" sid="58"/>
</provider>
FID=cc*256+sid=15*256+62=3902 REMARK: It's not always factor 256 for all FID calculations
PID=ltn1=30
RgnID=ltn2=32
VenID, use 1 for insert and 0 for remove
Via-Michelin (FR):
FID=cc*256+sid=15*256+58=3898 REMARK: It's not always factor 256 for all FID calculations
PID=ltn1=29
RgnID=ltn2=32
VenID, use 1 for insert and 0 for remove
Looking here in post #1 you can see the 2 code sets for France
It was a year or two since I've tried this calculations. I don't have the complete calculations for all providers but this can be used as a starter for further investigations. The hardest to calculate would be the FID if you don't have a real 25-character unlock key to investigate with [Only registered and activated users can see links. Click Here To Register...].Code:France, V-Trafic (FR): 3902, 30, 32, 1
France, Via-Michelin (FR): 3898, 29, 32, 1
EDIT: Here's some more examples of my own previous investigations.
Sample calculation with Radio SI/TrafficNav (SI)
:Anim3: State Type of license Ltn 1 Ltn 2 SID Radio SI/TrafficNav (SI) 9 1001 33 33 1 9=SL 1001 = lifetime Formula Value FID / MapID State*2^11+2^8+SID =9*2048+256+1 =18689 :Animated77: PID =Ltn 1 =33 RgnID =Ltn 2 same as Ltn 1 =33 VenID (1=insert) (0=remove) 1
Sample calculation for Destia Traffic TMC (PL)
:111anim: State Type of license Ltn 1 Ltn 2 SID Destia Traffic TMC (PL) 3 1001 5 5 2 3=PL 1001 = lifetime Formula Value FID / MapID State*2^11+2^11+2^9+2^8+SID =3*2048+2048+512+2 =8962 :Animated98: PID =Ltn 1 =5 RgnID =Ltn 2 same as Ltn 1 =5 VenID (1=insert) (0=remove) 1
Maybe someone could find the pattern for generic calculation of FID values for TMC?