According to Webopedia, T-1 or Trunk Line One is a dedicated phone connection supporting data rates of 1.544Mbits per second. A T-1 line consists of 24 individual channels, each of which supports 64Kbits per second. Each 64Kbit/second channel can be configured to carry voice or data traffic.

Within the communications world, trunking is analogous to the structure of a tree with one trunk and many branches. According to Wikipedia, this is exactly how trunking got its name. Trunking is a concept by which a communications system can provide network access to many clients by sharing a set of lines or frequencies instead of providing them individually.

T-1 lines are a popular leased line option for businesses connecting to the Internet and for Internet Service Providers (ISPs) connecting to the Internet backbone. Here are some more facts for your review:

• T-1 transmits digital signals instead of analog.
• T-1 connections are available in US, Japan and South Korea, while E-1 connections are available in Europe.
• T-1 PRI offers 23 channels and 1 additional channel to pass data such as Caller ID and improve performance. T-1 PRI is often used for call centers.
• A Bonded T1 is two T1 lines offering 3.0 Mbps of bandwidth.
• A T-1 line is either made of fiber or copper and T1 is being replaced by Fiber to the x (FTTx) technologies, which is a generic term for any broadband network architecture that uses optical fiber to replace all or part of the usual metal local loop used for last mile telecommunications.

Inphonite, LLC develops and markets professional, automated phone messaging systems and interactive computer telephony products that improve the profitability and productivity of a wide range of organizations. InphoniteVoice supports Digital, Analog and VoIP connections.

What is PBX? :
PBX (Private Branch eXchange) is a privately owned telephone switching system for handling multiple telephone lines without having to pay the phone company to lease each line separately. A PBX essentially takes the place of the phone company's Central Office within the company by acting as the exchange point, routing calls. With a PBX in place, each phone only needs an extension, not a phone number, and the PBX handles all calls made from desk-to-desk within the company.

Currently, there are four distinct scenarios in use:

1. PBX (Private and Circuit Switched)
   See definition above.
2. Hosted/Virtual PBX (Hosted and Circuit Switched)
   PBX is located at and managed by the telephone service provider, and features and calls are delivered via the Internet. You just sign up for a service, rather than buying and maintaining expensive hardware. This essentially removes the branch from the private premises, moving it to a central location.
3. VoIP PBX (Private and Packet Switched)
   Uses the Internet Protocol to carry calls. Companies need packet switched networks for data, so using them for telephone calls was tempting, and the availability of the Internet as a global delivery system made packet switched communications even more attractive.
4. IP Centrex or Hosted/Virtual IP (Hosted and Packet Switched)
   Combination of 2 and 3 above.

History of PBX and How it Can Help You :
Historically, the expense of full-fledged PBX systems has put them out of reach of small businesses and individuals. However, since the 1990s there has been a large set of small, consumer-grade and consumer-size PBXs available. And because of the scenarios above, you have many more choices on what can help your business specifically. Inphonite, LLC develops and markets professional, automated phone messaging systems and interactive computer telephony products that improve the profitability and productivity of a wide range of organizations.

• Open the InphoniteVoice Administrator Client and bring up the channel configuration:

• For each channel that you want be reserved for transfer capability, change the call direction to TransferOrConference.
• Change the Transfer Method property to Conference.
  
• After you have restarted the Inphonite Interface Service, you can monitor the status of the channels and verify your configuration by bringing up the Interface Monitor:
  

As you can see, "Conference" transfers are easy to set up, and best of all it works with anyphone line or VoIP provider.

Here is a link to a March 2009 article in Physicians Practice regarding appointment reminder systems by Jonathan McCallister.

• Low number of hops - less then 15 hops is ideal.
• Low latency - less then 100ms is ideal for jitter free VoIP calls.
• Multiple service location end points.
• If one data center is down you can reroute your calls to another location.
• Allows you to select the closet location with the fewest number of hops and the lowest latency.
  
• No monthly fees and low per minute fees.
• Maximum of 2 cents per minute. Discounts for volume are a good thing.
  
• Let's face it, there is no such thing as an "Unlimited" plan. Either you'll save money by just paying 1.2 cents per minute or the ITSP will cancel your account for excessive usage.
• Minimum of 10 concurrent call sessions (outbound). More capacity can be requested as volume grows.
• Supports inbound numbers for a low monthly fee.
• Per call outbound Caller ID - This is required for our Telephony SaaS application - InphoniteVoice.
• G729a support - Needed to compress calls without significant loss of quality.

• Gafachi - (www.gafachi.com)
• Voip.ms - (www.voip.ms)
• Teliax - (www.teliax.com)
  

• No investment in a PBX is necessary.
• Relatively ease and quick to implement.
• If the internet connection is down the provider can be configured to route calls to cell phones or other backup lines.
• Multiple internet connections can be used to provide connection redundancy.
• No need to upgrade the PBX as this is automatic when the VoIP provider upgrades there systems.
  

• If your VoIP provider is down your phones are down.
• If the VoIP provider has exceeded their maximum number of concurrent call sessions you will not be able to make an outbound call.
  
• Usually higher ongoing fees. Cost is usually priced per extension which can often be expensive for low volume users.
• Locked into the limits of the hosted PBX. If a custom feature or experience is require this can be expensive or impossible to add.
• Services like InphoniteVoice can be used to augment your Hosted PBX and provide custom, on demand solutions.
  
• Additional features usually add to the monthly fees.
• More difficult to switch between Hosted VoIP providers especially if your internet connection is provided from the VoIP company.
• Extension to extension calls routed over your internet connection unnecessarily using bandwidth.
  

• Multiple call routes can be created to provide redundant ITSPs.
• Multiple internet connections can be used to provide connection redundancy.
• Total control over the user experience. With the wide availability of tools on the market, companies with engineers can write custom applications to build a complete custom experience.
• Can interface with existing “legacy” phone connections for either primary or backup service.
• Easier to switch between ITSPs.
• Allows for integration with Unified Messaging platforms such as Exchange 2007.
• Usually lower ongoing fees.
• Extension to extension calls stay on your LAN or WAN.
  

• Upfront costs. You will need to buy and maintain a server and PBX software.
• More difficult and time consuming to implement.
• Requires a more technically savvy staff to configure and maintain.
• If the PBX is down your phones are down.
• May need to pay for upgrades to the PBX. Downtime risk when upgrades are performed.