ADSL Service Interruptions
One of the most common yet difficult to diagnose problems with ADSL service deals with service disruption. While there are all sorts of reasons, some of which will be recited to you ad nauseum when you call up your ADSL customer service line, one often overlooked yet major cause deals with a device called a Ho-anki (保案機). It's a device which acts much in the same way that a fusebox or utility meter box works, connecting the household circuitry with the main utility service outside on the street. (I'm only familiar with how this relates to apartments, so I'll gear my discussion for apartment tenants) For apartment tenants, the Ho-anki is a plastic case about the size of a small suitcase installed on the outside of your apartment building, usually streetside or where ever the phonelines from the street are connected to your building. I'm not sure if there is a standard look to it but since it's basically just a housing for switches, the outside shouldn't look so remarkable.
The symptoms of a Ho-anki problem include temporary disruption or disconnection of your ADSL signal growing more frequently over time, as well as static in your phonelines when you just pick up the receiver. Usually the static and disruption will worsen during inclimate weather and sometimes may sometimes inexplicably improve shortterm. When there is a disruption, the ADSL signal lamp on your modem will not indicate an ADSL signal or it will frequently go off, sometimes for short periods, or if the problem is really bad, for prolonged periods (days, months...). From what I know of Yahoo's ADSL trio modem, you can tell when the ADSL signal connects or disconnects by the clicking sound it makes.
Diagnosing this problem will take a call to NTT 116 help line. This is the hard part since you have YahooBB and NTT, too telecommunications giants who have a blood feud. You as the end-user need to do your homework regarding your ADSL service to make sure it isn't a software or installation problem, nor a matter relating to cables and plugs. If you had an ADSL signal and had been online successfully, but saw your connectivity degenerate overtime, then it will be easier for all parties to diagnose your problem. If you had never had an ADSL signal and had just contracted with YahooBB for example, then your problem will be compounded by your inexperience, and lack of a successful connection. Do your homework and work through the problem. See if you can convince yourself and others that your setup is correct and its definitely a hardware problem.
Visiting the local NTT office near Tsukuba Center will not help since the service counters are for phone service and contracting matters. If you are subscribing to an NTT phoneline and YahooBB, this service call and service visit should be free. Call 116, describe the problem, and if the situation warrants, NTT will send a small service van to your address. (Since the Ho-anki is just a readily accessible switchbox, you won't be seeing a truck with a cherrypicker (snorkel) or anything...probably, just someone with a ladder.)
The NTT repairman will go through the routine of narrowing down possible hardware problems by disconnecting the various devices which make up your ADSL setup, including your modem, phone, PC, phone jack, wall jack outlet, as well as all ADSL cables, etc. In the end, the repair guy will use that handheld phone receiver that phone repairman have to tap into your phone line, literally, to listen to the phone signal. Excluding any problems with the wiring within or outside the walls of your building, and also excluding any line problems on the street, the likely culprit will be the Ho-anki (保案機). You will probably not need to ask your landlord for permission to have this checked out.
While it is a part of the NTT phone service hardware,since it is installed onto private property, it probably does not undergo regular maintenance checks by either NTT or the apartment landlord. Overtime, this switchbox and the contacts inside will degrade through weathering, oxidation of the contacts, and sometimes foreign objects will get caught up with the electronic hardward (insects, webs, nests, lizards). The repair will consist of simply scraping the rust off the contacts, tightening a few screws, or just giving the hardware a good dusting. I guess, if things are really bad, a few parts may need replacing. If all goes well, Mr. NTT will close the box, the ADSL lamp on your modem will click on and hold steady, and there will be no bill. Your connection to the World Wide Web will be all set to go and you'll be able to watch those 2 crazy lip-synching Korean chicks on YouTube for the 10th time. Good luck.