For a more lengthy discussion on some of these considerations and related issues, see the DSL Overview appendix for more on modems, qualifying for service, and choosing a provider.
Once you have chosen a provider, and ordered service, the next step is for the telco to "qualify" your loop. This essentially means testing your line to make sure it can handle the DSL signal, and possibly what level of service may be available to you. This may take some time, especially if the telco encounters problems with the loop. If no problems are found during this phase, then possibly there will be a one to three week wait for the installation. YMMV.
After the telco has qualified the loop and readied their end of the connection, the next step is installation of the necessary components at the customer's end of the connection: wiring modifications, splitter or filters, and, of course the modem and any necessary software.
If you are not doing a self-install, then you may skip this section and move to Configuring Linux. If you are doing a self-install with microfilters, skip to the mircofilter section. The following procedures are meant to illustrate the wiring process. Please note that your procedures may be different at your location. Make sure you follow any warnings or safety instructions provided, that you RTFM, and that you are familiar with telco wiring procedures.
The first step will be to wire up the connections from your provider. Identify the line on which service will be installed, and the locations of your splitter and DSL jack(s). (For perhaps a better wiring scheme, see the Homerun section immediately below.)
Be aware that typical telco wire has more than one pair per bundle. Often, two pairs, but sometimes more. If you have but one phone line, the other pair(s) are unused. This makes them available for use with wiring for DSL. Wire pairs are color coded for easy identification. SDSL and IDSL require a dedicated, or "dry", pair. If an unused pair is available, then no real re-wiring is required. It is just a matter of re-wiring an existing jack for the correct pair of wires, and attaching the modem.
" I would not use microfilters if I lived across the street from my CO. A splitter is the only way to go. " | ||
--A retired BellSouth ADSL installer |
The optimum method of wiring for the DSL modem is sometimes called a "homerun". It is called this because it is one, straight shot from the splitter to the modem's DSL jack. What this does is bypass the existing inside wiring altogether, and any problems that might be lurking there -- like a corroded connection somewhere on a voice jack. Inside wiring deficiencies can cause a degradation of the DSL signal.
This also allows you to route the cable to avoid any potential RFI (Radio Frequency Interference) sources. RFI anywhere in the circuit can be a DSL killer. Routing the cable away from items that may have electric motors, transformers, power supplies, high intensity lighting fixtures, dimmer switches and such, is a smart way to go. And you are also less likely to have a failing microfilter cause problems -- one potential point of failure instead of several. You can also use a better grade of cable such as CAT 5.
If your existing installation is "splitterless" (i.e. using microfilters) now, converting to a homerun will entail purchasing a splitter. And, of course, will also mean some new wiring will need to be run. Microfilters also add to the effective loop length -- as much as 700 ft per filter in some cases! So if you have several microfilters installed, and your sync rate or distance is marginal, eliminating these filters may result in a significant improvement.
A poor man's splitter can be rigged by using a microfilter inside the NID. This is not "by the book", but seems to work just fine for many.
Ethernet modems will, of course, require an ethernet network card. If you haven't already done so, install the NIC in your Linux machine, configure the kernel, or load modules, etc., etc. This is sometimes the biggest stumbling block -- getting the NIC recognized and working. See the various Linux references for doing this, such as the Ethernet HOWTO for more information. Also, see the Troubleshooting Section below. This is certainly something you could conceivably do ahead of time if you already have the NIC.
Be sure the RJ45 cable between the NIC and the modem is now connected. You can "hot plug" this cable, meaning there is no need to power down to do this.
We can do a few quick tests now to see if the NIC seems to be functioning properly. First we'll attempt to bring up the interface. Then we'll see how well it is responding by pinging it. And lastly use ifconfig to check for errors:
# ifconfig eth0 10.0.0.1 up $ ping -c 50 10.0.0.1 PING 10.0.0.1 (10.0.0.1) from 10.0.0.1: 56(84) bytes of data. 64 bytes from 10.0.0.1: icmp_seq=0 ttl=255 time=0.2 ms 64 bytes from 10.0.0.1: icmp_seq=1 ttl=255 time=0.2 ms 64 bytes from 10.0.0.1: icmp_seq=2 ttl=255 time=0.1 ms <snip> - 10.0.0.1 ping statistics - 50 packets transmitted, 50 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.1/0.2 ms $ ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:50:04:C2:09:AC inet addr:10.0.0.1 Bcast:10.255.255.255 Mask:255.0.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:428 errors:0 dropped:0 overruns:0 frame:0 TX packets:421 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 Interrupt:10 Base address:0xc800 |
If "eth0" comes up without errors, and you can ping it without errors, and ifconfig shows no errors, we most likely have all our hardware in working order now, and are ready to start configuring Linux. If not, see the Troubleshooting section below.
Gotcha: A few modems may already be wired as a 10baseT crossover, and require a direct Category 5 cable for a direct connection to a NIC, rather than a crossover cable. I lost around 12 hours figuring this one out, so don't make the same mistake - make sure you RTFM first.
USB modems will require vendor and model specific drivers in order to sync and function properly. Assuming you are using the Alcatel SpeedTouch USB, this will require both a binary firmware driver available from Alcatel's driver page: http://www.speedtouchdsl.com/support.htm, and a separate modem driver.
This driver also supports both PPPoE and PPPoA, though the steps for getting either to work are quite different. See the Appendix for more on this modem.
The Eci Hi Focus ADSL Modem has some support in Linux now too. See http://eciadsl.sourceforge.net/.