Dulles, Va.-based AOL earlier this month began beta-testing AIM version 5.2, build # 3074, which gives users the ability to send IMs to another user's mobile phone, while also automatically forwarding incoming IMs to their own phone if away from their PC.

Both features are enabled through America Online's year-old AOL Alerts service, which offers SMS and IM notifications on sports updates, stock quotes and so on.

Sending an IM to a friend's SMS device is fairly straightforward, with the sender only having to add their contact's mobile number to their Buddy List. (AIM 5.2 adds a new button in users' Buddy List Setup screen, "Add Mobile".)

Only slightly more involved is setting up the IM Forwarding service. AIM users must first register their mobile device with AOL Alerts by clicking on a new button in AIM's Preferences menu. After signing up, the IM Forwarding service is activated automatically when a user is signed off from AOL or AIM, and all IMs sent to the user's AIM account after that point are redirected to the user's SMS phone from alerts@aol.com.

Limitations -- and New Directions?

In both cases, however, recipients are unable to reply to messages they receive on their mobile device. In response to IMing a mobile user, a sender receives a message indicating that the recipient received the message but cannot reply.

Presence information also is limited for mobile numbers and IM Forwarding users. As with AIM versions since 4.8, mobile device users are indicated by a cell phone icon, located next to their Buddy List entry. However, IM Forwarding and phone users cannot modify their status -- such as "Busy" or "Away" -- and thus, always appear able to accept messages, even if their phone is turned off.

(Technically, of course, their SMS accounts can continue to receive messages -- since SMS is a store-and-forward system -- but a mobile user would be unable to actually read them should their device be off.)

To deactivate IM Forwarding, a user must visit the AOL Alerts site through a special link embedded within the AIM application. This makes it problematic to stop receiving SMS messages if a user is unable to access their PC.

America Online has been working on the technology behind linking AIM with SMS for some time, however, and it's likely that AOL will have the capability to resolve several of these issues shortly.

For instance, mobile users' inability to control their presence via SMS would seem to be fixed easily enough. For months, AOL actually has had the ability to access AIM via 2-way SMS -- albeit through a kludgy, little-known implementation. Under this system, users can log into or off of AIM, or view Buddies' status, by sending SMS messages to an AIM server.

Clearly, that system (dubbed "AIM Service Using Text Messaging") has its drawbacks. Sending a message to a Buddy requires requesting and remembering a special ID number, making the process time-consuming and awkward -- one of the reasons, perhaps, that the SMS-based service has seen little significant marketing. Indeed, it's typically something of an afterthought for many carriers, who already offer AIM embedded in some of their higher-end mobile devices, or via WAP.

Nevertheless, the AIM Service Using Text Messaging does at least offer backend support for logging off, altering presence and responding to IMs via SMS -- features that we might see beefed up in future AIM releases.

Making Good on Promises

On the much-touted ICQ compatibility front, there seems to have been little progress since last month. In October, AOL announced that it would eventually allow some measure of interoperability between its two services, which operate from the same servers. The company provided no timeline.

In AIM Version 5.1, which went to beta in November, AIM users gained the ability to include ICQ users in their Buddy Lists. But as of the 5.2 beta, the client doesn't yet support actually sending messages to them.

The 5.2 beta also shows little advancement in another closely watched area: it does not yet support SSL-based encryption, a feature important in AOL's B2B strategy. In November, the company introduced its gateway for administering AIM use in the workplace, with features that included support for secure messaging among enterprise users.

An AOL spokesman said that later beta releases of version 5.2 might include support for encryption.

In any case, the updates to AIM's compatibility with SMS mark new development in America Online's ongoing "AOL Everywhere" initiative, intended to spread its online and instant messaging services to non-PC devices.

In late 1999, AOL acquired Tegic Communications, a startup best known for developing technology to simplify text entry -- particularly AIM use -- on cell phone and small-screen devices. Tegic also marketed a wireless IM product, which now functions as a part of AIM's wireless SMS-, Java- and WAP-based versions.

A year later, America Online began offering the AOL Mobile Communicator, a rebranded Research In Motion BlackBerry mobile device that supports AIM. In recent months, AOL also has been active in reaching agreements with many U.S. carriers to support embedded or WAP-based clients on their higher-end phones and devices.

In addition to contributing to its "AOL Everywhere" initiative, the new beta also comes as the latest in America Online's rapid-fire upgrades to AIM. Once testing on version 5.2 is complete, it will supplant AIM version 5.1, which in turn replaced the two-month-old version 5.0 in November.

Christopher Saunders is managing editor of InstantMessagingPlanet.com.