V.92 Modem Standard (Issue 1030)


Read this article for everything you ever wanted to know about the V.92 modem standard.


What is V.92?
V.92 is the new dial-up modem specification from the ITU (International Telecommunications Union) that introduces three new features that will add convenience and performance for the modem user. The three features are quick connect, Modem-on-Hold™ (MOH) and PCM Upstream.

What is the ITU?
The International Telecommunications Union (ITU) is a formal, worldwide telecommunications standards body. The ITU is a charter organization of the United Nations (UN), and is based in Geneva, Switzerland..

What makes a V.92 modem faster than V.90 modem?
The quick connect feature of a V.92 modem cuts the modem negotiation or handshake time by up to 50% so you can dial-in faster. The main feature that makes a V.92 modem faster than a V.90 modem is V.44 the new compression protocol. It is based upon a compression scheme that can speed up your web browsing as much as 50%. Not all V.92 modems are required to have V.44 data compression..

Why do I need or want V.92?
Although broadband technologies (DSL and Cable) are all the rage right now, in reality, most people around the world only have access to analog phone lines. Dial-up modems will remain the primary means to get on the Internet for several years, so it is important to improve the user experience on this technology..

How do V.92 modem speeds compare to ISDN, ADSL and Cable speeds?
The V.92 modem is a regular dial-up modem with increased speed. ISDN (64-128Kbps), ADSL (640Kbps and up), Cable (1000Kbps and up) and other broadband connections have a higher "raw power" connection speed so they will continue to be faster than a V.92 modem..

What will quick connect do for me?
Very simply, quick connect will shorten the time it takes to make a connection by remembering ("training") the phone line characteristics and storing them for later usage. Typically, the modem handshake (all that noise you hear) takes from 25 to 27 seconds. Surveys indicate that people are quite irritated at this length of time. Quick connect will cut the modem handshake time in half for most calls, a significant improvement..

Will quick connect work for me while I'm on the road with my laptop?
Yes. Since quick connect actually "trains" the modem on the first call, all the following calls will be quick connects - faster handshake times. People usually make more than one connection from the same phone line (e.g. hotel) when they are traveling..

What will PCM Upstream do for me?
PCM Upstream boosts the upstream data rates between the user and ISP to reduce upload times for large files and email attachments. A maximum of 48 Kbps upstream rates is supported. PCM Upstream will work particularly well with new equipment such as Internet-connected digital cameras, which primarily upload rather than download information..

Will I be able to upgrade my V.90 modem or will I have to buy a new V.92 modem?
Some of the older V.90 modems that were upgraded from x2 or K56Flex to V.90 do not have the hardware needed to implement V.92. In those cases, you would have to buy a new modem to get V.92 capabilities. All other modems should be V.92 upgradeable..

When will I be able to buy V.92 modems?
V.92 modems are available now..

What will MOH do for me?
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.

How much time will I have if I choose to take an incoming call?
Your ISP defines the "hold" time. The V.92 specification allows for hold times to be anywhere from 10 seconds to infinite.

Do I have to redial to get back to the Internet?
No. When you hang up the phone you can resume browsing.

Can I stay on the Internet and make a phone call?
Yes. Initiating calls is easy with MOH. First, a MOH application is executed. This program suspends the data connection between your modem and the ISP so you can pick up your phone and make an outgoing call in the usual way. The application puts the modem "on-hold", flashes the hook, and a dial tone appears on the extension handset so you can make a call. When your call is complete, the modem will detect an extension on hook, flash the hook twice, and return to the data (Internet) connection.

How long will I have before the Internet connection is dropped?
Again, your ISP determines the hold time. For example, the MOH application can display the time allotted and also display a countdown so you will know how much time you have left for the phone call.

What services do I need to use MOH?
For the purposes of this document, we will use Telco terms that are used in the United States. These services may be called by a different name in other countries. First and foremost, you must have Call Waiting in order to take advantage of MOH. CallerID (CID) is not required. There are 2 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, but it does require hardware support on the modem board if you want to use this feature via the modem. This is because without specific hardware support, there is no data path from the telephone line to our modem device when the modem is in the on-hook condition.

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 a 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, for CID on CW, the user must have CID on Call Waiting (not just CID) service from the Telco.

Where can I get a MOH software application?
We expect that most modem manufacturers will supply a Modem-on-Hold applet with the modem driver. Check with your modem manufacturer for details.

What is V.44?
A new link-layer compression standard based on technology developed by Hughes Network Systems, V.44 will replace the current V.42bis compression technology. V.44 offers a higher compression ratio than V.42bis.

What will V.44 do for me?
Higher compression ratios mean that more data can be downloaded in the same amount of time. The most significant improvement will be noticed when you are browsing and searching the web, since HTML text files are highly compressible. For most users, data throughput will be increased by 20 to 60%.

Is this the last standard development for analog dial-up modems?
New features are proposed to the ITU every year, so it is not out of the realm of possibility that we will see new developments for the analog modem in the next year.

What is NetWaiting™?
NetWaiting (a BVRP application) is bundled with the Conexant V.92 modem chipset and driver. In NetWaiting's initial release, Call Waiting is supported for the US, Japan, China, Israel, France, Italy and Singapore. Call Waiting CID is supported for US, Japan, Israel, France and Italy. More countries will be added over time.

NetWaiting, like all MOH applications requires the user to have Call Waiting service with their telephone company. Additionally, Call Waiting must be enabled. Some ISPs (e.g. AOL) automatically turn off Call Waiting in their dial up scripts.


V.92 modem