hi all,i have a problem about the a 3100 infinity modem.when i enter the rlock in telnet interface,modem response ; REMOTE STATUS: LOCKED

how can i resolve this problem?

this is the link a picture ;

https://img694.imageshack.us/img694/2238/lockedo.jpg

The "problem" is that your service provider has locked the remote to only operate on their network.
This is a design feature idirect have built to allow service providers to more actively control the distribution of remotes.  often service providers will give away a modem with a defined contract time, if the user decides to end the agreement early by taking the modem to another service provider, the modem will not operate on the new system.
the rlock can only be removed from the modem with the password used in to lock the modem in the first place.  
You have 2 options:
1. Contact your service provider  and ask for the modem to be unlocked
2. contact iDirect directly with proof of ownership, they may be able to issue a 1 time unlock code.
for 1. above, the provider will only do this if you have met your obligations under their contract.  i doubt they will otherwise.
for 2. above iDirect will not unlock this without confirmation from the recorded owner of this unit.  So if your service provider is the registered owner and does not authorise iDirect to unlock it, they will not.
If you have purchased this unit without contract and are now unable to use it, I would contact the person who retailed the unit and ask them to rectify the situation.

I know idirect have really tightened up their game on this aspect. Remember, their customer is the service provider/reseller, not the end user, so they have an obligation to them to ensure the rules are strictly adhered to.

You may get replies on here telling you to contact people on the side to gain unlock methods, be VERY CAREFUL of anyone who tells you they can unlock modems for you, a lot of users suggest a downgrade and use with a service provider on a lower SW version (they are generally after your business), this may or may not work temporarily, but as soon as the service provider upgrades, service is lost again as the modem is locked.  also be very wary of people advising opening the box up and carrying out work on the board, this is very dangerous and can effectively turn your investment in a modem into an expensive paperweight.
Sorry to bear bad news, but it is a pretty tight function and the best way is to amicably agree with the service provider/retailer a way to progress.