Internet Phone VoIP Hardware Requirements for Internet Telephony

Hardware

To set up a little VoIP system the following hardware is needed:

• A PC, 386 or more
  
• A sound card, full duplex capable
  
• A network card or connection to internet or other kind of interface to allow communication between 2 PCs
  

All these have to be present twice to simulate a standard communication.

The tools above are the minimal requirement for a VoIP connection.

Real situation

Next we'll see that we should use more hardware to do the same in a real situation. The sound card has be full duplex unless we couldn't hear anything while speaking! Additional hardware cards can be used to be able to manage data stream in a compressed format.

Hardware accelerating cards

Special cards with hardware accelerating capability can be used. They are:

• Quicknet PhoneJack
  
• Quicknet LineJack
  
• VoiceTronix V4PCI
  
• VoiceTronix VPB4
  
• VoiceTronix VPB8L
  

Quicknet PhoneJack is a sound card that can use standard algorithms to compress audio stream like G723.1 (section 4.3) down to 4.1 Kbps rate. It can be connected directly to a phone (POTS port) or a couple mic-speaker. It has an ISA or a PCI connector bus.

Quicknet LineJack works like PhoneJack with some addition features (see next).

VoiceTronix V4PCI is a PCI card pretty like Quicknet LineJack but with 4 phone ports

VoiceTronix VPB4 is a ISA card equivalent to V4PCI.

VoiceTronix VPB8L is a logging card with 8 ports.

Hardware gateway cards

Quicknet LineJack and VoiceTronix cards can be connected to a PSTN line allowing VoIP gateway feature. A software will then be needed to manage it.

Software requirement

We can choose what O.S. to use. The most common are the following:

• Win9x, Win2000, WinXP
  
• Linux
  
  

Under Windows we have Microsoft Netmeeting, Internet Phone, DialPad or others or Internet Switchboard for Quicknet cards. Note well, however, that the latest Quicknet cards using Swithboard (older version too) NEED to be connected to Internet to get working for managing Microtelco account (not free of charge), so if you plan to remain isolated from the Internet you need to install OpenH323 software.

Under Linux we have the free software GnomeMeeting, a clone of Microsoft Netmeeting, while in console mode we use (also free software) applications from OpenH323 web site: simph323 or ohphone that can also work with Quicknet accelerating hardware. Note that all Openh323 source code has to be compiled in a user directory (if not it is necessary to change some environment variable).

Gateway software

To manage gateway feature (join TCP/IP VoIP to PSTN lines) you need some kind of software like this:

Internet SwitchBoard (only when connected to Internet) for Windows systems also acting as a h323 terminal;
PSTNGw for Linux and Windows systems you download from OpenH323.

Gatekeeper software

The following can be chosen as gatekeeper:

Opengatekeeper
Openh323 Gatekeeper (GK)

Other software

An example of a useful h323 compliant software is Phonepatch, which is able to solve problems behind a NAT firewall. It simply allows users (external or internal) calling from a web page (which is reachable from even external and internal users): when web application understands the remote host is ready, it calls (h323) the source telling it all is ok and communication can be established. Phonepatch is a proprietary software (with also a demo version for no more than 3 minutes long conversations).