VoIP is not one product or service; it has many facets. Different parts of the telecom industry (manufacturers, carriers, software developers, system integrators, and more) play different roles in VoIP implementation. The different facets can either extend or retrict telecom accessibility, as shown in the table below.
Definition |
Negative Implication |
Positive Implication |
|
Segment |
VoIP is used in a transmission facility for a portion of a PSTN, but calls begin and end on non-VoIP equipment. Late Breaking News: On April 21, 2004 the FCC ruled that this is a "telecommunications service", and therefore regulated. |
"VoIP insertion" is unknown to and uncontrolled by the end user so accommodation is not possible; TTY performance and audio quality may be degraded. | Lower cost to carriers may result in less expensive service. |
PBX |
VoIP is used as the only protocol within a private network (owned and managed by an organization such as a company, municipality, university, etc.). The PBX is connected to the public network. | The management of the organization purchasing the PBX may not consider needs of users with disabilities. PBX selected by the organization may lack important accessibility features. The organization may administer the PBX so as to limit its accessibility. Employees with disabilities may not be able to choose accessibility solutions (for example, if the PBX uses only inaccessible proprietary phones). Inaccessibility may affect both employees and callers from PSTN. |
Voice and data integration may allow improved accessibility within organization and to external callers, such as unified voice and text messaging, TTY gateway. |
Hardware |
Device designed to be used for VoIP calls, including phones, adapters, and routers | Phones may have been designed without attention to the accessibility of physical controls, TTY connectability, and displays |
|
PBX softphones |
Software that emulates a PBX phone's functionality, sometimes integrated with related applications such as email and instant messaging. | Softphones available for any given PBX may not be accessible. | Some softphones are highly compatible with assistive technologies. Some softphones have their own screen reading capability. Hard of hearing users can select audio output devices and adjust them for optimal use. |
Internet peer-to-peer softphones |
A softphone intended for a PC user to place and receive direct VoIP calls over the Internet, without a carrier. | Profusion of softphones may complicate finding one with the accessibility features needed by any given individual. | Low cost telecom service. Profusion of softphones may provide a wide range of accessibility features. Hard of hearing users can select audio output devices and adjust them for optimal use. |