I alluded last time to the ever-increasing volume of client device options that enable voice calls using wired and wireless phones of various technology flavors, plus laptops with softphones and PDAs that have communications capabilities. By purchasing products onesy-twosy and without a structured plan in place, knowledge workers could wind up with any number of devices. Not only is this expensive and a management challenge, it can be a security risk. It is easy to lose gadgets, and the smarter phones get - with data access capabilities and IP addresses in them - the more useful they are to someone who might steal or find one.But let's get back to the issue of "voice management."Cisco, for example, has long positioned its wired voice-over-IP\u00a0(VoIP)\u00a0phones as a mobility play. You can carry your handset around the company, even across geographical site boundaries, plug it into any Ethernet jack, and automatically get recognized for who you are with all access rights and your IP PBX extension intact. That's pretty cool.But as of this month, Cisco also offers its own 802.11b-based wireless VoIP phone, the 7920, also billed for mobility, of course. Now these handsets are not really all that cheap. Do you really need to spend another $595 for a wireless VoIP phone for users who already likely have, at a minimum, a desktop phone and cell phone (particularly since PBX calls can be forwarded to the cell phone)?On the other hand, perhaps 802.11b phones will be used primarily in warehouses, retail, or healthcare environments where shift personnel can share them. Sharing a phone across multiple workers makes the cost more reasonable, and these are the types of workers not likely to be in the vicinity of an Ethernet jack at all times and for whom the organization may not wish to invest in a cell phone.Conversely, perhaps wireless VoIP phones will eventually replace the wired VoIP phone. And we still need to integrate IP PBX features with cellular features. All this is speculation.I don't believe we'll ever get down to a single, "nirvana" client device, because voice and data needs are just too different. But when it comes to phone calls, I think we need to find some guidelines for accommodating the cross-section of traveling knowledge workers with the appropriate combination of laptop, PDA, and some mix of phone(s).