Dial-up technology still accounts for 70 percent of the market and so modems will remain the primary means to get on the Internet for several years. Rajiv U elaborates on the latest technology in the modem market called V.92

One might wonder if there is a real need for improvement in dial-up modem technology in today’s broadband world. The answer is simple: YES. Because although broadband technologies (DSL and Cable) are being aggressively promoted, most people around the world only have access to analogue phone lines. Dial-up technology still accounts for 70 percent of the market and so these modems will remain the primary means to get on the Internet for several years. Therefore it is important to improve on this technology.

V.92 is the latest dial-up modem specification or standard from the International Telecommunications Union (ITU) that introduces new features for the dial-up Internet user.

What is new in V.92?
V.92 introduces three new features that will add convenience and performance to the modem for the Internet user. These are:

• Quick connect—cuts the modem negotiation or handshake time by 50 percent so you can connect faster.
• Modem-on-Hold (MOH)—allows you to receive an incoming call and stay connected to the Internet.
• PCM Upstream—boosts the upstream data rates between the user and ISP at a maximum of 48 Kbps.

V.92 vs V.90
The quick connect feature of a V.92 modem cuts the modem negotiation or handshake time by up to 50 percent so you can dial-in faster.

Many households use the same phone line for both voice calls and data (Internet), so when the user is browsing the Internet, an incoming call cannot get through. MOH allows you to receive an incoming call and stay connected to the Internet (call-waiting service from your phone company is all that is required). It also works in reverse; you can initiate a voice call while connected and keep the modem connection.

Today, with V.90, you can get a maximum of 56 Kbps downstream and a minimum of 33.6 Kbps for the upstream. In the case of V.92, while the speed downstream is the same, the upstream is significantly faster at 48 Kbps. The cost of ownership reduces in terms of Internet usage with the Internet speed increasing on upstream also.

How fast is V.92?
The main feature that makes a V.92 modem faster than a V.90 modem is V.44, the latest compression protocol. V.44 is a new link-layer compression standard that will replace the current V.42 compression technology found in today’s V.90 56 Kbps modems. It is based upon a compression scheme that can speed up Web browsing as much as 50 percent. V.44 offers a higher compression ratio than V.42.

The difference between a V.92 modem and ISDN, ADSL and Cable is that the V.92 modem is a regular dial-up modem with increased speed. ISDN (64-128 Kbps), ADSL (640 Kbps upwards), Cable (1,000 Kbps upwards) and other broadband connections have a higher ‘raw power’ connection speed so they will continue to be faster than a V.92 modem.

How soon will ISPs support V.92?
Historically, new communication standards are made available in client modems before the network modems, and this will be the case with V.92. Leading network equipment manufacturers have tested V.92 and a number of ISPs have V.92 ports available. Of course, not all ISPs will upgrade to V.92 at the same time.

The ‘hold’ time (to answer incoming calls) on this modem is defined by the ISP. The V.92 specification allows for hold times to be anywhere from 10 seconds to infinite. And in fact you do not have to redial to get back to the Internet. When you hang up the phone, you can resume browsing.

There are different types of caller-ID (CID) formats available from telephone companies. For the purpose of better understanding in this article we will use terms that are used in India.

First and foremost, you must have the ‘call-waiting’ facility in order to take advantage of MOH. CID is not required.
There are two types of CID, Type 1 and Type 2.

Type 1 CID is a service that allows a telephone subscriber to receive information on the incoming call before the user (or modem) takes the call by going off-hook. Sometimes called on-hook CID, it does not require call-waiting option, but requires hardware support on the modem if you want to use this feature via the modem.

Type 2 CID (also referred to as CID on call-waiting) does not require hardware support on the modem board. Type 2 CID is not required for MOH to work. However, without Type 2 CID support from the Telco, the user will not be able to receive details (telephone number) of the incoming third-party call. For the purposes of an MOH discussion, we will only refer to Type 2 CID.

In summary, for MOH functionality, the user must have call-waiting service from their telephone company at a minimum. Optionally, the user must have CID on call waiting (not just CID) from the Telco.

In fact, not every international telco offers CID on call-waiting as a commercial package, even if it is supported in the equipment. First, check with your telephone company to see if call-waiting CID is offered as a service. Second, check with your modem manufacturer for a list of countries supported.

The author is head of the marketing & sales division at Select Technologies. He can be contacted on rajiv@select-technologies.net