ISDN Pricing

• The Qwest charges for an ISDN line after all the taxes and franchise fees are added is about $85/mo. Qwest can provide more detailed information. Qwest does not offer a "residential" price for ISDN. It can be installed in houses or apartments, but the price is the same as a business would pay. The install fee is approximately $110.
• SWCP charge for ISDN Internet service: $25/month for 125 B-channel-hours/month, $0.20/hr for extra time.
• SWCP also offers dedicated (24/7) ISDN Connections: $100/mo for a single channel connection (56k/64k), $175/month for two channel connection (112k/128k), with a $20 setup fee.
• You can mix single and dual channel use. You're charged for actual usage.

For example, if a you connect only with ISDN single-channel 64k connections, then you can use 125 hours. If you always make bonded 128k connections, you only get 62.5 hours.   You can mix these freely, you could use 25 single-channel hours plus 50 dual-channel hours.

Some TAs (Terminal Adapters) have a feature called Dynamic Bandwidth Allocation (DBA) or Bandwidth On Demand (BOD) which allows the user to dynamically use the 2nd channel only when needed. For example, you can configure DBA to bring up the 2nd channel only if the line is loaded at >80% for more than 10 seconds, and drop the 2nd channel as soon as utilization drops below 50% for more than 10 seconds. In that way, the user would have the 2nd channel available when she needs it (when downloading large files), but wouldn't have to pay for it when she doesn't need it (reading email and news, and most browsing).  Many TAs do not support DBA. In this case, the user must decide at call setup time whether to establish a connection with 1 channel or 2.

Background

ISDN (Integrated Services Digital Network) is a digital replacement for one's home or business analog telephone line. Instead of using a modem to convert your computer data into audible tones and sending them to another modem to be decoded back into digital data, it uses a digital connection all the way through from one end to the other. This makes it much faster, more reliable, and easier to use.

There are two types of ISDN lines, Basic Rate Interface (BRI), and Primary Rate Interface (PRI). Virtually all SWCP customers will be using BRI. A BRI consists of 2 64k B-channels ("bearer" channels, the lines that will carry your data), and one 16k D-channel. The D-channel is used for out-of-band signaling and does not carry user data. For example, the D-channel is used to tell the phone company what number to dial, or to receive caller-id information, etc. This configuration is sometimes called "2B+D".

To use an ISDN connection, you need an ISDN Terminal Adapter (TA), sometimes called an ISDN modem. This box serves the same logical purpose that a modem serves, it connects your computer to the telephone network and allows you to dial a number and make a connection. There are three basic types of TA's:

• Modem replacement - simple, not a lot of features, internal or external.
• Network ISDN modem/router - connects to the phone network and to a LAN to allow multiple computers to access the network.
• ISDN Telephone - looks like a regular telephone, may have a serial port to allow a computer to connect.

The two B-channels of an ISDN line can be used to make two independent voice phone calls, or one voice call and one data call, or two independent data calls, or a single "bonded" 128k data call. Most TAs other than ISDN routers will probably not allow two separate data calls to different systems. All TAs should allow the other connection types, with varying degrees of flexibility.  The protocol used to bond two B-channels into one connection is called Multilink PPP, variously abbreviated as MLPPP, MPPP, or MP.  To support analog calls (voice, fax), the TA must have analog ports on it. Most modern TAs do, but not all of them. The analog ports are just RJ-11 jacks like you would find on a modem, and you can plug any old analog phone handset into them. Most TAs are smart enough to automatically drop one channel of a bonded connection when you pick up the phone (without interrupting your data connection) and re-bond the 2nd channel to the data link when you hang up the analog phone.

Provisioning an ISDN line

Qwest offers ISDN service in New Mexico. It is not available in all areas, but it is in most. Some "outlying" towns have ISDN available but require extender technologies which carry an extra monthly fee (Los Lunas and Placitas are examples of these communities).

Qwest ISDN is available in most of Albuquerque, including the South Valley, Corrales, and Rio Rancho. Service is also available in Los Alamos, White Rock, and much of Santa Fe.

To install ISDN, the copper phone line must be conditioned by Qwest. The line must also pass certain tests in order to support ISDN. You can call the Qwest order number to have them do a "loop qualification" to determine whether your location is already "loop qualified". If it is, installation should happen fairly quickly (within 3 weeks). If it is not, then Qwest will still take the order, but there may be delays while they condition the line to support ISDN.

You must be located within about 3 miles a Qwest CO office that supports ISDN.

The customer must provide a clean Cat-3 (or better) cable connection from the demarcation point (where the phone company installs the line) to the jack that the ISDN TA will plug into. This may mean you may need to hire a wiring technician to run a cable or ask Qwest to do the internal wiring when they install the ISDN line (there is an extra fee for this). Cases where this might be needed:

• The house wiring is too old (houses more than 10 years old are suspect)
• You don't want to disturb existing analog lines
• Distance from demarc to TA is too long -- if it's more than a couple hundred feet, you need good shielded cable for the run.