ohphoneX Manual


  1. Introduction
  2. Hardware/Software Requirements and Installation
  3. Getting Started
  4. H.323 and ohphoneX Preferences
  5. Working with ohphoneX
  6. Miscellaneous
  7. Known Bugs
  8. Glossary


In this section, you find a short explanation of some of the commonly used terms in conjunction with VoIP telephony.

CIF defines an image frame size. The size is 352x288 pixels.
QCIF stands for Quarter-CIF, which means that the frame area is a quarter of the area from CIF. Therefore, the size is 176x144 pixels.

E.164 Number E.164specifies a number under which you register at a gatekeeper. This is usually the same number as the regular phone number.
For more information on this topic, please consult the System Administrator which runs the gatekeeper you are planning to use.

G.711 is an audio codec which offers standard phone audio quality. This is the standard audio codec in the H.323 protocol specification.

A gatekeeper is basically a directory which maps your ip address to your username and/or phone number (E.164 Number) By using a gatekeeper, other persons can call you by entering your name or phone number. So, as long as your gatekeeper registration is up-to-date, you can be reached wherever you are on this world, no matter what your current ip address is.
For more information on this topic, please consult the System Administrator which runs the gatekeeper you are planning to use.

H.245 is a multimedia protocol that allows clients (sometimes also referred as endpoints) to negotiate which multimedia services to use, based on a so-called capability list.

H.261 defines a video codec. This is the standard video codec in the H.323 protocol specification.

H.263 is another video codec. This codec uses less network bandwidth by offering the same or even better image quality. Not all H.323-Clients do support support the H.263 codec.

H.323 is a communication protocol that allows clients (sometimes referred as endpoints) to establish a multimedia connection.

LAN stands for Local Area Network. The network at home or at a company is considered a LAN since it often uses Private IP Addresses and is bridged to the rest of the internet through a router and a NAT.

NAT stands for Network Address Translator. A NAT is used to connect a LAN with the rest of the internet with one single external ip address. The NAT translates a request originating from your private ip address into a request from your external ip address. The response from the internet is then translated back into your private ip address and sent to your computer.

Private IP Address
The Internet Consortium defined some ranges of ip addresses to be for private usage. The most commonly known is the 192.168.xxx.xxx range.

SIP is another communication protocol similar to H.323. SIP is not supported by ohphoneX at present time.