DSL Modem Guide FAQ

dsl modem questionsThere are many common questions out there about DSL modems that either go without being answered or are answered incorrectly.  This is a basic guide to the most common of questions regarding DSL modems and the correct answers to the questions being asked:

Question #1: What do Downstream & Upstream Mean?

Answer #1: Downstream and upstream speeds are references to how much data a DSL connection or modem can receive and send in any given second respectively .  These speeds are generally rated in either kilobits per second (Kbps) or megabits per second (Mbps).  Generally speaking, bigger numbers are highly desirable if performance is an issue.

Question #2: What is ADSL?

Answer #2:  ADSL stands for asynchronous digital subscriber line, and it describes any type of DSL situation where the downstream and upstream speeds are not 1:1.  In almost all cases the downstream speed is going to be significantly higher than the upstream speed.  This means that you can usually download far more data than you can upload or send out in the same period of time.   ADSL speeds range from very affordable to very expensive depending on the market, but are generally considered to be one of the more affordable types of broadband offerings.

Question #3: What is SDSL?

Answer #3: Synchronous digital subscriber lines, or SDSL, are DSL-based connections where the upstream and downstream speeds are equal.  These connections tend to be more expensive than their ADSL cousins and are often used by small and medium sized businesses that run their own web-connected hardware or by consumers that do a great deal of uploading to photo, video, or other data-intensive sites.

Question #4: Is SDSL Better Than ADSL?

Answer #4:  It all depends on how you plan on using the connection.  Anyone that uploads, hosts services or sites, or does a lot of outbound data will probably appreciate SDSL since it is nearly impossible to find ADSL solutions with greater upstream than downstream capabilities.  Average consumers probably like the savings and performance that ADSL has to offer.

Question #5: Which DSL Modem Standards Do I Need to Look For?

Answer #5: It all depends on your carrier.  Some carriers use ADSL vs. ADSL+ or ADSL2, while other carriers use VDSL, and yet other carriers may require bonding.  Be sure to check with your local carrier to know what standards are required if you are not going to buy one of their modems.  There are also other standards to consider such as encapsulation and PPPoA & PPPoE, but virtually all modems support these standards as appropriate based on the DSL specification(s) that use them.

Question #6: What Are PPPoA and PPPoE?

Answer #6: In both acronyms the PPP stands for point to point protocol, but the A and E stand for ATM and Ethernet respectively.  While the technical details of these standards may not be worth getting into, the fact is that PPPoA has the tiniest of technical advantages over PPPoE when it comes to raw performance.  Most modems support both standards so it rarely matters what your ISP requires in terms of login and data transmission protocols for PPPoA and/or PPPoE.

Question #7: Where Can I Buy a DSL Modem?

Answer #7: Most DSL carriers actually offer modems at a great discount if you sign up for a plan, but there are always vendors willing to sell you modems if you are so inclined.  You can generally find the best deals online, which may be ironic since you are shopping for a device that will connect you to the Internet.  Failing that, you can often find modems at local stores that sell electronics.

Question #8: What is an Integrated Ethernet Switch/Router?  What About Wireless?

Answer #8: Some people have many wired devices or computers that they wish to connect to the Internet, and as such modem makers offer DSL modems with the integrated capability of doing just that without the need to purchase another piece of equipment.  Some manufacturers are even adding wireless capabilities to their modems to let wireless devices share the DSL connection without additional hardware.

Question #9: Will my ISP Support a 3rd Party DSL Modem?

Answer #9: It all depends on your provider, but the answer is becoming yes with an asterisk more often than not.  That asterisk is that there may be a fee for such support, but that may or may not be a bad thing depending on the situation.