|Home||Reviews||Tools||Forums||FAQs||Find Service||ISP News||Maps||About|
how-to block ads
1.1 DSL Technology
A normal phone line to your home is comprised normally of 2 parts; an F1 is the main feed cable from the central office to a CrossBox. It is a direct shot. The F2 is from that crossbox where it spider webs in different directions to the actual pedestal or telephone pole that is going to connect to your house. There are also 2 other options. If the central office is a fiber or T1's feeding a Pair Gain unit which multiplexes up to 24 numbers per T1 line, than can also be the F1, with the F2 going from the Pair Gain to the crossbox, and then an F3 from the crossbox to the pole or pedestal near your house. There's also some that have a direct connect from the central office to a pole or pedestal near their house. In that case they only have an F1.
Anyway, when they say they are conditioning the cable, it doesn't really matter if they say F1, F2, or F3. The conditioning is still the same. They are either taking load coils out (Cleans up a pair of wires because of extremely long distances. Gets rid of noise from inductance and AC); removing bridge taps (When the same cable pair goes to more than 1 pole or pedestal so it's available in more than one location so when it's not used in one place, it can be used some place else); repairing a cable that is on the brink of failing; or re-routing pairs and dedicating them to get the most direct shot without having the bridge tap issue I just mentioned.
Assuming that there isn't an F3 in the case of a pair gain, a normal F2 conditioning is taking out load coils and/or bridge taps.
got feedback?]: »Re: Goodby Qwest!
Excluding web/mail servers and the like, a DSL connection consists of the following path elements (applies specifically for non-FTTN):
1. Local loop- copper between the DSLAM and the customer modem.
2. DSLAM trunk- ATM T1s, DS3, or OC3.
3. ATM cloud- the ATM switches and internodal trunks between switches.
4. ISP trunk- the ATM trunk (T1s, DS3 or higher for 3M and above customer speeds) that feeds the ISP gateway router.
Elements 1-3 are the same (depending on the ATM cloud path) regardless whether Qwest or a 3rd party ISP like Xmission are providing IP services. 4 will be different, as it's a dedicated trunk to the ISP router. So while much of the network is the same, it's not completely the same physical network.
[Added by [ christcorp ]: Let me add one caveat. Some ISP's offering DSL do have their own DSLAMS in town. As such, #1; their local loop many times would be a dry pair of wires from their home/business to their ISP's DSLAM. In this case, other than a cross connect of copper, not of Qwest's DSL path is shared with the customer or his/her ISP. later... mike...]
»DSL FAQ »DSL and HOME ALARM SYSTEMS.
»AT&T Southeast Forum FAQ