• Sidebar: Two IM Clients for Windows Mobile

Corporate users of newer Windows Mobile Smartphones and Pocket PC phones will be soon able to access instant messaging (IM) and presence services provided by Live Communications Server (LCS) 2005 systems. A free client, named Communicator Mobile, will let users of Windows Mobile 2003 Second Edition and Windows Mobile 5.0 devices exchange instant messages with other LCS users and, in some cases, conduct Voice-over-IP (VoIP) calls with users on PCs or Windows Mobile devices.

The new Communicator Mobile client is unrelated to the MSN Messenger client that comes preinstalled on all Windows Mobile devices. (For details on how the two clients contrast, see the sidebar "Two IM Clients for Windows Mobile".)

Fills a Key Gap

Microsoft is gradually filling the gaps in its products for real-time communications (user presence, IM, telephony, VoIP, video, and data conferencing) both inside and among organizations. In 2005, the company extended secure and auditable IM and presence services to Internet users and other organizations that run LCS 2005; it released a Web-based client for LCS 2005 and a new desktop client, Office Communicator 2005; and it added new telephony capabilities. The combination of LCS SP1, Communicator 2005, and a gateway to the PBX allows users to control PBX functions, such as dialing numbers or setting forwarding options, from the Communicator 2005 client, and users can conduct VoIP calls with other Communicator 2005 users and those on the public switched telephone network (PSTN).

Although these telephony capabilities allow users to automatically forward calls placed to their PBX extension to their cell phones, those users cannot use the built-in MSN Messenger IM client on their Windows Mobile devices to send or receive IMs on the LCS system or hold VoIP conversations. When users leave their PCs, LCS flags their presence status as unavailable even though their Windows Mobile device might still be connected to a data network.

The forthcoming Communicator Mobile client, expected for release in mid-April 2006, can change this. It is based on the full Communicator 2005 client and supports the Session Initiation Protocol (SIP) and SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) standards, but it is tailored for the smaller screens and different user interfaces of Windows Mobile devices. When the device is connected to a corporate Wi-Fi network or to the Internet over a public Wi-Fi network or a cellular data network, users see the presence status of their contacts and can exchange IMs with them. If the organization has federated its LCS system with other organizations or with public IM providers (AOL, Yahoo, and MSN), Communicator Mobile users can even exchange IMs with contacts outside their own organizations. However, using Communicator Mobile's two-way IM functionality will be easiest and fastest on devices that have built-in QWERTY thumbboards.

Windows Mobile devices equipped with Communicator Mobile will also be able to receive one-way notifications from any application that uses LCS to alert users of significant events. This capability will make automated notifications much more effective, as users typically have their phones on them when they aren't sitting at their PC; and because the notification messages are one-way, it doesn't matter if the mobile device lacks a keyboard.

VoIP Support Limited

While Communicator Mobile introduces full support for presence and text IM, it only adds limited support for VoIP calls.

If the user has a Windows Mobile 5.0 device with Wi-Fi support, users connected via Wi-Fi directly to their corporate network will be able to exchange VoIP calls with PCs with Communicator 2005 or mobile devices with Communicator Mobile connected to their network. Furthermore, if the organization has installed a PSTN gateway between their LCS 2005 system and their PBX, these Communicator Mobile users will be able to place VoIP calls to PBX extensions and PSTN numbers in the same manner as Communicator 2005 users.

The Communicator Mobile client also has the same limitations as Communicator 2005. Users cannot receive calls from other PBX extensions or from PSTN-based callers. Furthermore, because LCS 2005 does not natively support VoIP calls across a firewall, users connecting from the Internet cannot use the VoIP capabilities of either client.

Because Microsoft did not release extensive details on the capabilities of the Communicator Mobile client, several questions remain. Microsoft did not clarify whether VoIP will work if a user is connected to a public Wi-Fi or high-speed carrier network but has established a virtual private network (VPN) connection back to the corporate network (thereby virtually placing the device inside the corporate network). Communicator Mobile's VoIP integration with the Outlook Mobile contact list is also unknown, but it seems likely that users will be able to dial voice calls from within their Outlook Mobile contact lists and receive caller ID pop-ups when an inbound call matches an Outlook contact, similar to the way the desktop versions of Communicator and Outlook work together.

Licensing and Resources

Even though the client software is free, users must still have an LCS 2005 Client Access License (CAL), which covers both mobile and desktop access. Furthermore, users of Communicator Mobile's VoIP capabilities must also have an LCS 2005 Telephony CAL, which covers both mobile and desktop telephony functions.

More detail on Microsoft's real-time communications offerings (and links to the download page when Communicator Mobile becomes available) can be found at www.microsoft.com/office/uc/default.mspx.

Microsoft's foray into telephony is described in "Taking Another Stab at Telephony" on page 9 of the Oct. 2005 Update.

Microsoft's IM solutions are detailed in "LCS 2005 Takes Corporate IM Beyond the Firewall" on page 3 of the Jan. 2005 Update and in "IM, VoIP, Conferencing Roadmap Unveiled" on page 10 of the Apr. 2005 Update.

The Web client for Live Communications Server 2005 is described in "New Web Client for Live Communication Server" on page 7 of the Feb. 2006 Update.