In an earlier article I described the productivity, management, and control advantages of implementing fixed mobile convergence (FMC) using cellular service in conjunction with the simultaneous ring/extension to cellular on IP PBX systems. While these solutions deliver the baseline benefits of FMC, one-number accessibility, single voicemail, and control of the telephone number, there is more to FMC than just telephone calls.
It is critical that enterprise users look at the overall plan to deliver mobile unified communications, and not just the short-term objective of making a phone call. Without a well thought out plan, they risk burdening themselves with solutions that cannot evolve to meet those changing requirements. What’s more, a poorly planned installation can open the voice network to potential toll fraud or theft of service.
When it comes to integrating cellular services with the IP PBX, there are two different ways the solution can be implemented. The difference will define the convenience and functionality the user experiences. I classify the approaches as one-path and two-path systems.
- One-Path systems utilize a standard cellular handset that is not modified in any way. All communications and signaling are handled over the cellular voice path. With simultaneous ring, this handset can be linked to the user’s desk phone, and incoming calls are rung simultaneously on the desk set and the cell phone. For outgoing calls the cell phone dials into the IP PBX, and the IP PBX places an outgoing call to the recipient. Signaling between the mobile and the IP PBX is done with traditional inband DTMF (i.e. “Touchtone”).
- Two-Path systems utilize the cellular voice service for the voice transmission, but it is used in conjunction with a cellular data service (e.g. EDGE, HSDPA, 1xRTT, EV-DO) that carries signaling messages between the handset and a mobility server on the IP PBX. These handsets require a special software client. As with the One-Path solution, all incoming and outgoing cellular calls are routed through the IP PBX, but the Two-Path solution can deliver a richer mobile unified communications experience to the user.
Both implementations will provide the baseline benefits of one-number accessibility, single voice mail, and the organization maintains control of the telephone number (i.e. customers and other contacts are always calling a business number, not the user’s personal cell number). Further, routing cellular calls through the PBX allows us to track usage with the IP PBX’s call detail recording. It is important to recognize that these solutions will likely result in higher calling charges, so organizations should look carefully at the network costs before deploying the capability to a large number of users.
While they do require a cellular data plan for each user, Two-Path solutions can deliver a major leap in functionality as the cellular data service allows a number of unified communications features to be extended to the mobile user. First, the mobile user can view the corporate directory along with the presence indications on their mobile handset. As with a desktop UC dashboard, the mobile user can then click-to-connect. They also have the capability of four-digit dialing for PBX station-to-station calls. Incoming calls, the even though they are routed through the IP PBX, are delivered with the caller ID of the actual calling party, rather than the number of the IP PBX. Not all solutions incorporate all of these features, but at the high end, it’s almost like having a PBX station in your pocket.
Mobile Two-Path users can also have visual voicemail, or the ability to display all the voice mail messages they received along with the calling numbers. They can listen to them in any order, or delete messages on issues that have already been resolved. Busy users can blow through their voicemails in a fraction of the time it would take to listen to each of them in turn.
The Two-Path operation does result in a different experience when placing outbound calls from the mobile however. You recall that all outgoing calls are routed through the IP PBX. When the mobile user dials or clicks to originate a call, a signaling message is sent over the cellular data service to a server on the IP PBX, and the server then instructs the IP PBX to call that mobile subscriber. The mobile user hears their cell phone ring (you check to be sure it’s the IP PBX that’s calling), and as soon as the mobile subscriber answers, the IP PBX places the outgoing call. It might take the user some time to become comfortable with that operation.
The enhanced functionality of the Two-Path solution requires a smart phone and a special software client in the mobile. The vendors typically support a limited range of smart phones using either the Symbian, Windows Mobile, or Blackberry operating systems. The key to user acceptance will be to first allow the user to see how the mobile operation works, and then try it for a few days to see if they can accommodate themselves to its somewhat quirky operation. If they can live with a new way of placing outgoing calls, we can deliver a lot of enhanced mobile functionality as a result.
A One-Path solution forgoes the special client software and works with any cellular handset, but it delivers only the minimal functionality. That simplicity also comes at the price of increased security risk. To place an outgoing call in a One-Path solution, the mobile device calls into the PBX, the PBX verifies the mobile by its caller ID, and then allows the user to dial the outgoing call using the DTMF capability in the cell phone. That means the PBX is allowing a trunk-to-trunk call, opening a potential for theft of service. In the standard implementation, the PBX is depending on the caller ID to authenticate the fact that it’s a valid user placing that outgoing call. Unfortunately, it’s not difficult to spoof caller ID, so that mobile user could be sharing his or her outgoing call privileges with anyone. You can add another level of protection be requiring the mobile user to input a PIN code when they are placing a call, but if we put the mobile user through that much trouble to place a call, they’ll probably go find a payphone!
The toll fraud exposure does not exist with the Two-Path solutions, because the IP PBX is calling out; the mobile user is not calling in. Also it does not exist with the Two-Path FMC solutions from companies like Agito or DiVitas, because the incoming cellular call goes to a server that sits on the station side of the IP PBX, and the server authenticates the caller before it allows the outgoing call to be placed. The PBX does not have to allow trunk-to-trunk calling, as the outgoing call appears to be coming from a station.
Mobile unified communications has opened a wide range of possibilities in enterprise communications, but user acceptance is still a critical element in the mix. Mobility is one of the most recognizable benefits of unified communications, and in our dynamic business environment these solutions can deliver improved accessibility, enhanced productivity, and faster decision making. However, we still have to deliver a capability that offers an acceptable mix of functionality and convenience in a secure manner.
By the way, I’ve written an extensive white paper on FMC Options for the Enterprise that can help bring you up to speed on the various solutions, how they work, and the benefits they can provide.