ISDN

• What is ISDN?
• Who can get ISDN?
• Why would I want ISDN?
• What are some of the disadvantages?
• How much does ISDN cost?
• How do I choose an ISP for ISDN?
• How do I get ISDN?
• 24x7 connections and static IPs

ISDN stands for Integrated Services Digital Network.

Back in the early 1980s, the ISDN standard was developed as an international standard to complete the change of the phone system from incompatible analog systems to a single global digital standard. This conversion is similar to the switch from VHS tapes to DVDs, and for many of the same reasons.

There are many advantages to the phone company to have an all digital phone system - but the final mile - the copper wire that runs from the phone company's digital switching center to your house - has remained analog because of the huge expense involved in converting the existing equipment.

ISDN developed a reputation in the US in the 1990s for being overpriced and very difficult to get working. Telephone staff had not been properly trained in its deployment, and the terminal adapter equipment was difficult to configure and maintain.

ISDN quickly developed the joke that if you called the phone company and asked about ISDN, the person was likely to prove that "I Still Don't kNow". Protected monopolies have a way of getting indifferent to their customers.

While ISDN did reach some level of use in special applications - like radio shows where the host calls in from another city but sounds like he is in the studio - Rush Limbaugh is an example- ISDN never really reached the consumer market in a significant way. Most installed ISDN equipment is intended for small office users.

After DSL was invented and started to roll out, it largely pushed aside the need for ISDN, and ISDN faded quickly (about 1997) - however ADSL has one very serious limitation - it only works reliably out to a little over 2 miles from the phone company's central office. It also cannot work on lines with some types of problems, and cannot work over lines using a device called a digital loop carrier. DLCs were installed to reduce the amount of copper needed and to pave the way for the all digital revolution.

The good news is that ISDN is now a mature technology and tariffs and surcharges have become much more reasonable in many states.

ISDN is widely available, and can work easily out to 18,000 feet. Beyond 18k feet, ISDN will still work but may require a repeater. Beyond one repeater (35,000 feet), ISDN gets harder to implement, but still could be available. Your biggest obstacle may be finding someone at the phone company that is "in charge" of ISDN and can place the order and supervise the installation.

ISDN works much like a normal analog phone, except that the signal is much clearer. No high frequency filtering is done, so the phone is full fidelity and static free.

An ISDN circuit consists of two digital channels, each of which can either be used as a voice call, or a digital computer call. If the 2nd line is not in use on a voice call, both channels can be bonded to provide a single 128 Kb/sec channel.

A 128 Kb bonded channel is about 2.7 times as fast as a perfect analog modem connection, and much faster than that in "real life" applications.

v.90 modems are only 33.6 Kb/sec inbound into the internet, while a 2B ISDN connection is 128 Kb/sec in both directions - so the inbound (upload) about 4 times as fast as a v.90 modem. v.92 modems may someday get up to 48 Kb/sec inbound, but that is largely unproven in the real world.

This inbound speed difference is important if you do FTP transfers to maintain a web site, run a mailing list from your PC, or run peer to peer file sharing software (only legal non-copyrighted files - of course!), or want to use high bandwidth services like two way video conferencing (it still won't be great, but a lot better than v.90).

Almost all phone companies today have digital phone switches in their central offices - converting switches was the most important part of completing the conversion to digital. In most places, this was done more than 20 years ago. Unless there is some type of line impairment that would prevent ISDN, it should be available as an ordinary tariffed product almost anywhere.

Here are some of the reasons you might want to get ISDN:

• Faster transfer rates and more reliable connection than analog dialup, especially with compression.
• Connections are full bandwidth at all times, no modem retraining, no line quality related disconnects
• Running a home or small office network where DSL is not available
• Faster call setup - no modem sqawking - 2 seconds and you're online
• Clearer voice calls
• Unlike DSL, you are not locked into one specific ISP for your email and internet access (See SBC/Yahoo or Qwest/MSN for examples). You can switch ISPs as easily as you can with your analog modem if you have problems with the ISP or it goes out of business.
• ISDN can make a reasonable emergency backup for other types of broadband in the event your DSL, T1 or Frame relay connection goes down.

• Dialup ISDN is -NOT- an always on connection. However, it takes so little time to connect that it is painless to drop the connection when idle and reconnect - but be sure you understand how the tariffs work in case there is a per call charge. Dedicated ISDN is also available - see below.
• Your phone company still may not be very interested in selling ISDN to you. The Telcos are more interested and familiar with rolling out DSL. You may need to run through the phone company phone maze to find someone who has correct tariff information and can place an order.
• Cost - ISDN tariffs have dropped a lot and most ISPs have dropped or eliminated surcharges for ISDN, but ISDN still may cost more than DSL or cable - especially if you are stuck with a per minute or per call charge from the phone company. There also significant costs for new wiring and equipment.
• You can't take ISDN "on the road" - since ISDN is a special type of phone line to your building, if you take your computer away from home, you'll still need a modem because you're back using an analog phone line. If you want to use the internet away from home, make sure the ISP permits you to dial in from an analog (v.90/v.92) modem away from home (or get a cheap bare bones Bargain v.90/92 account if they don't).
• The day after you get ISDN working, your phone company might tell you that DSL is now available to you because they decided to install a remote DSLAM in your neighborhood, so the money you spent on ISDN was wasted.
• ISDN needs electric power - unlike your old phone line, ISDN is not powered from the central office. If your electricity goes off and you want the phone to still work, you need backup electrical power for the phone to work.

In order to understand how much it costs for ISDN, you need to compare what you have now with what you have after you install ISDN.

Typically, an ISDN line is going to replace two analog phone lines, so if you have a line for your phone and a line for the computer or fax machine, one ISDN line replaces both of those lines - although you may want to keep one analog line active for a month until you are sure the ISDN is working correctly.

An ISDN circuit includes two phone lines. So, the higher line cost for ISDN is offset by the cost of the two analog phone lines. You'll probably find that the monthly cost to the phone company is fairly close IF you don't have per minute or per call charges. In a few places, the costs may be less.

Your phone company probably has a Residential ISDN tariff and a Business ISDN Tariff. The Residential Tariff is generally less expensive, and in some cases waives or reduces the per minute charges.

Probably the single most important thing to look for is that the ISP has experience with ISDN. Call them up and ask to speak with the person who knows about ISDN. Based on this page, you can probably think up a few questions to ask the ISP. If the ISDN guy only comes in on the third Thursday of the month, you're talking with the wrong ISP. If the person who answered the phone knows the ISDN answers, that's a great sign.

The ISPs that responded with thorough answers to our ISDN survey were:

• The Link
• CyberConnectics
• Great Lakes Internet Service (Michigan only)
• Toast.net

Their interest in taking the time to contribute to this page indicate a comfort level with ISDN that should be considered when you look at the list.

Basically, there are two different ways that an ISP can sell you ISDN. One is with a nationwide partner, almost always Megapop or uu.net. These networks have state of the art ISDN equipment and lots of experience, but that also makes it harder for the ISP to solve problems if issues come up.

The other way ISDN is provisioned is you dial into a POP that is run by the ISP. In that case, they have complete control over the configuration and can work more directly to resolve problems - however, that probably limits your choices to an ISP that is in your city, or your part of the state.

Because of tariff issues, CLEC competition and advances in technology, ISPs which run their own ISDN POPs are rapidly going away and being absorbed by the big networks mentioned above.

Please be careful to ask which ISDN services an ISP offers on what phone numbers.

Part of this is a limitation with our directory - we can't tie different pricing and hour limitations to specific access numbers, but that is often the case with ISDN pricing.

There are ISPs that offer services from 3 or 4 networks in your town, all of which probably have equipment that is ISDN capable, however the ISP may only offer ISDN service through one of the networks, or may have different numbers of hours or special restrictions on some of the networks.

Once you've narrowed down the list, absolutely call the ISP and make sure that the ISDN number you intend to dial can be used by the service plan you are considering buying - 128k bonding and Static IPs in particular.

If you are ordering 128K (2B) ISDN from the ISP, it is important to understand the pricing. We've found that some ISPs don't even understand their own pricing - especially if its provided by a third party network.

ISDN is almost always billed based on channel hours. When you are connected with both channels, you are consuming 2 channel hours for each hour that both channels are online.

Some ISPs quote the total number of channel hours included, others state the limit based on the assumption that both channels are online at all times - 200 hours really means 400 channel hours. In a few cases, ISPs have said it is the total number of hours connected, without regard to whether you are using one channel or two.

If you expect to use a lot of channel hours, but only use the connection heavily part of the day, look for Dial on Demand. If your terminal adapter is configured to use this feature, initially you only connect on one channel. If your demand on bandwidth starts to exceed what one channel can do, the terminal adapter dials in the second channel and bonds it on the fly. When your demand for bandwidth drops back down, the second channel is dropped, which then conserves your allocated channel hours.

To get ISDN functioning, you need several steps:

• You need to order the ISDN circuit installation from your local phone company
• You need to buy a terminal adapter for your computer and phones.
• You may need to have wiring changes inside your house or business
• You need an ISDN dialup account with an ISP

Ordering the ISDN circuit may be very easy or very hard depending on your phone company. The ISPs that do business with Ameritech indicate that ordering ISDN is very simple. Other parts of the country report the process is much more tortured. Before placing the order, be sure you understand the installation costs and the monthly costs for your location. Consider whether it makes sense to leave the analog phone line in place for a month of overlap.

Tip: If you have a working cell phone, you might be able to use it during the transition, especially if you can call forward your landline calls to the cell phone.

Back in 1994, when there was confusion about the ordering process, standard terminology was developed. If you want the ability to use voice and data, ask for "Capability Package S". If you only intend to use data, then order Capability Package "R". If your phone company understands what you mean when want Capability Package S, then you won't get hit with a checklist of features that you probably don't understand that could result in an installation that doesn't work.

If you intend to use 128Kb (2B) ISDN, you'll want to make sure you have equipment that supports Dial on Demand (using BACP) to only use the second channel when it is needed. (Part of capability S)

Be sure to order the plan that offers unlimited minutes or a per call charge, not per minute. If you are told there is no such plan, don't accept that as the final answer. Check with your state public utilities commission to see if that's really true. If it is, consider putting pressure on your elected representatives to have your state force the phone company to offer such a plan.

If you want the ability for an incoming voice call to knock down the second channel so you can answer the phone and stay online at 64k, you'll need to order "Additional Call Appearances" (or Additional Call Offering - ACO) - roughly similar to Call Waiting and make sure your equipment supports the capability. Related to this, you probably want to be sure that the first SPID# rolls over to the second channel if the first one is busy. If you are actually using the two channels for different voice purposes (your phone and a phone for the children), you may not want to do that.

When you pick up the phone to place an outgoing and both data channels are in use, you you will want the T/A to dump the 2nd channel. This feature is called "Channel Preemption".

The phone company may recommend a specific brand or model of terminal adapter. They cannot require you to use any specific brand or model, only that it conform to the international ITU ISDN standard. BUT if there is one model that they use a lot, the installation may go smoother. Your ISP may also have opinions.

The phone company will be glad to do the inside wiring changes necessary, for their tariffed fees. If you have your own phone installer or are reasonably handy, do the work yourself. What you need is internal wiring to be run from the demarcation point (the Network Interface Device (NID)) to the room with the terminal adapter. You might just reuse the existing twisted pair, if you can be out of service while the insallation is underway.

You should decide on your T/A equipment before ordering the inside wiring. You MAY need an RJ45 phone jack (normal voice jacks are RJ11) Some ISDN TA/routers come with a cable that has RJ45 on one end and RJ11 on the other end, making a special RJ45 jack unnecessary.

For Dialup ISDN, you want to order a Multipoint circuit, not Point-to-Point (Multipoint is part of the Capability package S).

For each channel, the phone company will assign you a SPID, which is an ISDN phone number. It is usually possible to keep the same phone number you have today for one of the SPIDs, but that can complicate the installation process.

It is possible you may be told that your central office is not ISDN capable, but that service can be provided out of another nearby central office. Be sure you understand what your local calling area is in this situation. This might even work to your advantage!. If the phone company later does install ISDN capable equipment in your CO, you may be forced to switch back to the closer CO and have to change phone numbers.

Equipment

There are three basic choices for how to connect your ISDN - which is right for you depends on your situation.

If you plan to connect more than one computer through this connection, you want an integrated router and ISDN adapter -or- a terminal adapter plus a standalone router.

If you only plan on using ISDN on one computer, you can get by with an internal PCI ISDN card, however you'll then have your phone line(s) running through your computer, which means your phones may not work if your computer isn't powered up. You may not want to do that.

Among the ISPs that responded to our survey, they suggest:

• Netgear RH-338
  (TOAST.net, Great Lakes)
• 3com ISDN LAN Modem
  (CyberConnectics, TheLink)

The terminal adapter generally has one or two phone jacks to allow you to connect your existing analog telephones into the ISDN line (through the terminal adapter). If you have phone jacks throughout your house, unless you want to replace your phones with ISDN phones, you'll need to connect the analog output on the terminal adapter to the existing phone extensions using an RJ11-RJ11 cable (and disconnect that circuit for the NID so it isn't being fed from both the NID and the TA).

The other component you need is to connect the ISDN equipment to your computer. Most of the products use Ethernet. If your PC does not contain a NIC (Network Interface Card), you need to buy one - these are very inexpensive these days ($20 will buy an adequate one). Most new computers have the NIC built into the computer.

Some of the newer ISDN equipment can connect using USB. While that might work, that is combining an a mature technology (ISDN) with an evolving technology (USB), and you may find support to be a problem.

If you use a terminal Adapter on a PCI internal card in your PC, no other connections, cables or NIC are needed. Several brands of internal T/A's are available for $100-$150 retail.

When comparing equipment, be sure you are looking at ISDN-U (United States) equipment - not ISDN-S/T (Europe). If you have S/T ISDN equipment, you'll need to buy another device called an NT1 to convert to/from ISDN-U. A device with ISDN-U has the NT1 built into the equipment, instead of being a separate box with its own power supply.

If you want to be the biggest geek on your block, you could install an NT1 at your NID, and then rewire your house running 8 wires to every jack, which you switch to RJ45. You buy ISDN phones, and an ISDN capable Fax machine, and then you can truly say you are completely Digital and be the envy of your friends.

This is how phone systems in much of Europe do work - the phone company installs and controls the NT1. That works much better to get a country to be all digital. But we still measure in miles and gallons in the US because we can.

One ISP strongly recommended against trying to buy ISDN equipment from online auctions. It is likely to be broken, old equipment, the wrong model for the US, obsolete software, a model not compatible with your version of Windows, etc...

You are looking for a equipment with a BRI interface, not PRI. PRI is 24xBRI and the prices reflect that.

If you are running a relatively small office network, you might want to consider ISDN if you cannot get DSL - and a fractional T1 circuit or Frame Relay are too expensive or problematic.

For a 24x7 connection there is a basic choice between a dialup connection that permits you to be online 24x7 vs. getting a true "dedicated" ISDN connection.

An ISP offering "unlimited" ISDN does not necessarily mean you can use it 24x7, but some do offer that for around $100-$150 a month, typically.

Read carefully or ask the ISP.

*IF* your phone company tariffs do NOT carry per minute charges, using dialup for 24x7 ISDN has the advantage that it doesn't lock you into one ISP. But keep in mind since this -is- a dialup connection, the phone company may periodically disconnect the phone call and require the equipment to redial.

A Dedicated ISDN circuit does no dialing - when your computer powers up, it is immediately online connected to your ISP. Dedicated ISDN is 128Kb/sec - two permanent B channels. Dedicated ISDN is only going to be available where the ISP owns and runs its own POPs. Should you later decide that you're not happy with that ISP, or the ISP goes out of business, you'll need to have the phone company install a brand new circuit to a different ISP.

The installation of a dedicated ISDN circuit is done by the ISP, and then you pay them a fee to cover the phone company costs plus their work to get the connection functioning properly. The ISP frequently will require a one year or longer commitment on this type of installation.

If you want to run your own email server or web server in your office, you'll need static IP addresses, which are more appropriate for a dedicated connection. Note that unless your servers are very light duty, hanging them from an ISDN connection is a really bad idea.

Putting your server(s) in a well connected collocation facility is a much better idea and will cost less in the long run in most cases and they will be more reliable and perform better.

If there is some compelling reason that you -need- the server in your building, consider frame relay (burstable) or a T1.

Most facilities have the ability to backup the servers, provide good security, reliable electric power and fire suppression. That addresses most of the reasons people feel a need to be able to reach out and touch their computer.

If you can get ISDN, another option is IDSL - which is DSL routed over ISDN. IDSL is 144/144 DSL over the dedicated ISDN circuit instead of 128/128. Because it generally terminates at collocated equipment at the phone company, instead of backhauling back to the ISP's computer room, you may find that IDSL is less expensive than dedicated ISDN.

About DLCs

You may have been told that the reason you can't get DSL is that your line has a Digital Loop Carrier. These were installed both to pave the way for the all digital future in the 80s and 90s, and to reduce the need for copper, especially in congested urban areas and newly settled rural areas.

Instead of needing 96 pairs to your neighborhood, 10 pairs are used to feed the DLC. The DLC then is the digital endpoint, and your current phone is only analog from the DLC out to your building.

If you are fed by a DLC, you are a perfect candidate for ISDN, as all of the equipment is already in place and no repeaters will be needed.

The current trend is to now replace those 10 copper pairs with a fiber optic cable, which can then feed many hundreds of copper pairs from each DLC - copper only for the final few blocks to your place. Remote equipment like DLCs and remote DSLAMs are important technology for phone companies, but the high cost of installation usually needs a concentration of people close together to justify the cost.