PBX Systems

Overview

A Public Exchange (PBX) is a device that routes phone calls. As it applies to Small Businesses, it is an appliance or server that routes incoming calls to various extensions in the office, and routes outgoing calls from the various extensions to the outside world. As they existed several decades ago (see picture on the right) a person was required to connect cables between a caller and a callee in order to connect the two. In the days of modern computing, connecting calls can be handled by a computer. And the computer can provide many more functions, such as Voicemail, Time Conditions, and Call Forwarding, and can connect callers and callees to these services.

Choices When Purchasing a new PBX

Analogue or Digital or Hybrid

If reliability is the most important requirement, then you want a PBX that can connect to analogue phones lines.

In the case of those of us living in the Yukon, that means connecting to NWTel phone lines. Special hardware is required to be installed in the PBX computer to connect to NWTel's analogue phone system, making the installation more expensive. Additionally, phone lines are considerably more expensive than the digital options, making the ongoing expense of maintaining your PBX higher. The benefit to having a system that can use analogue lines is that down time of the system is typically going to be less than 8 hours per year, achieving a 99.999% uptime (5 nines).

Digital phone lines, often referred to as VoIP, are considerably less expensive than analogue. Phone lines are still purchased in the same way they are from NWTel, but they come from a VoIP provider, and they work over an existing internet connection instead of a dedicated copper wire. No special equipment is needed for the server, and the lines are far less expensive. Additionally, most VoIP services provide free long distance calling in Canada, and free or pennies per minute calling the US. Additionally, calling to worldwide numbers is generally very inexpensive, though that is not true of every single foreign country. So there is a very strong economical argument to use digital phone lines. The downside to digital lines is that they cannot be any more reliable than the internet, so one can expect to have about 2-4 days of down time across a year, giving approximately 99% reliability (two nines instead of five). Often that comes in the form of a few hours at a time which accumulates to a few days by the end of the year, but it can potentially include a full day of downtime.

Hybrid systems provide the best of both worlds. It can save a lot of money by allow the inexpensive or free long distance calling, but still requires installing the special hardware in the PBX server and having analogue lines from NWTel. The PBX server is configured to send outgoing calls through the VoIP provider by default and fail over to the analogue lines when all VoIP lines are in use, though any combination of restrictions can be configured. Another limitation to hybrid systems is that they have 2 phone numbers; one from nwtel, and one from the VoIP provider, and when you call a callee, their phone will display a different number depending on which service the call goes out over, and someone calling into the system can use either number.

Once all the lines are in simultaneous use, no additional calls will be possible into or out of the system. When choosing the number of lines you want, you will want to guess how many maximum concurrent calls will be in play at any given time, and add one line just in case someone calls in while all the other lines are busy. If all lines are busy and someone calls into the PBX system, that caller will get a busy signal. One thing to note with hybrid systems is that while outgoing calls can fail over from the VoIP provider to NWTel phone lines, incoming calls cannot. So if all VoIP lines are occupied with outgoing calls while someone calls in to the number provided by the VoIP provider, they will get a busy signal even if none of the NWTel lines are occupied at all.

Desktop/Conference/Cordless/Software Phones

Phones (mostly called SIP Phones or IP Phones) that connect to a modern PBX run across the same kind of network connection that your computer uses. While it is easy to think of the phones as analogue devices like what you have at home, they are actually more like little minicomputers.

Most desks do not have two network plugs in the wall (one for the computer and one for the phone), so pretty much all desktop phones have the ability for the computer to plug into them, and then they plug into the wall jack, thereby connecting both devices through the same wall jack. This saves having to run extra cabling in the wall. The less expensive phones quite often limit network speeds to 100Mbit, so this can pose problems if the software you are using on your computer requires a Gigabit connection. A good example of this is Sage; if two people are working on the same company file, a 100Mbit connection will be noticeably slower than a Gigabit connection.

The high end desktop phones usually have much bigger and colour screens, and often support video calling capabilities. The lower end ones are considerably less pretty, do not usually have colour screens, and will not have near as many features, but they will be more than sufficient in the vast majority of use cases. The extremely low-end phones will lack some very common and useful features such as audio compression and echo cancellation.

Receptionists will quite often want sufficient buttons that they can answer calls and transfer them to various extensions. Some models of phones can have sidecars installed on them specifically for this purpose.

Conference phones are designed to sit in the middle of a room so that multiple people can be talking and listening to the same phone. These phones tend to be more expensive, and most of them have multiple high quality microphones in them so that they can do noise cancellation to clear up the ambient sound of the room and make the call quality clearer. They can also have extension microphones attached to them for larger boardrooms.

DECT phones, which are basically like the cordless phones you are used to at home, can also be connected to the PBX. These have a base station that connects to the computer network, and then can support a handful of DECT phones that connect back to the base station wirelessly. Range on these units is not bad, will cover most offices, but probably not most warehouses, to give an example. These phones can be a bit finnicky in comparison to desktop phones, especially when the place they are being deployed at has a lot of metal or other material that interferes with wireless signals.

Software phones are available as free or paid for software, and can be installed on mobile devices such as Android or iPhones, or computers and used with a headset that includes a microphone. These can be considerably less expensive than their hardware counterparts, but are generally not as intuitive to use as the traditional phones. The best purpose for using this kind of phone is if the end-user is working remotely, but wants to connect to the PBX to make or receive calls.

Power

SIP Phones will most often have an option to come with a power adapter so that they can be plugged into an electrical outlet in the wall. Unfortunately a significant amount of the time such power outlets can be in short supply at a busy desk, so the vast majority of SIP phones are capable of using a thing called Power over Ethernet (PoE).

PoE carries power to the phone through its network cable, and requires a specific kind of network switch to work. These switches are more expensive than non-PoE switches, but have several advantages. One advantage is that there are several kinds of devices that can be powered in this way besides the phones. Good examples of this include wireless access points and security cameras. Another really big advantage is that a single battery can power the PoE network switch, which can give the phones and PBX server some run time during power outages. In some cases this can be critically important; for example if someone does not have a cell phone but needs to call 911 when the power is out.

Since these switches and batteries can be quite expensive, they are more suited to larger installations, but small offices that utilize their PoE switch to power multiple types of devices other than the phone can still find them cost effective.

DECT phones are much like cell phones in that they have a battery, and charge by sitting in a little cradle that plugs into a wall or computer through a USB cable. The associated base station can often be power by PoE, but if not they can get their power from the wall.

Feature and Options Available

• IVR (Interactive Voice Recording) - often called an Auto Attendant. This is when someone calls into your phone system, and the phone system answers and provides option for the caller to choose from, without the need of a person.
• Voicemail/Unified Communications - Voicemail has been with us for quite a long time, and probably needs no explanation, but it can be accessed remotely. Unified Communications is the ability to make your Voicemail inbox and your email inbox to function as the same inbox. Voicemails that are left will show up on the phone, and as an email message; and when it is marked as read or deleted in either email or phone, the same will happen on other devices. This requires an IMAP capable email server.
• Time Conditions - have the phone system play different message during holidays or off-hours than it does during regular work hours. Possibly also have incoming calls routed to a cell phone or similar during off-hours.
• Ring Groups - incoming calls can be routed so that multiple extensions ring at the same time.
• Find Me/Follow Me - provide an option for an incoming caller to try reaching a person on a cell phone if not available at the desktop extension; or have other extensions or cell phones to ring automatically when a call is received by your extension.
• Call recording - configure the system to record phone calls for various purposes, can be configured to happen on demand or automatically.
• Intercom/Paging - use a single phone to broadcast a message to all other phones
• PIN Restricted Long Distance Dialing - do not allow calls to long distance numbers without knowing the code
• LCR (Least Cost Routing) - configure the system to choose the path that will cost the least amount of money (useful on hybrid systems)
• Staff Directory - provide an option for incoming callers to find an employee by name when they don't know the employee's extension.
• Conference Calling - If sufficient lines are available to connect to the PBX, have dozens or hundreds of people call into the system and use a conference room. PIN restricted access is available.
• Calling Queus - When more people are calling in than there are people to answer the calls, place the incoming calls in a queue so the next available representative can answer the incoming calls in order. This is familiar to most of us when calling into larger companies; it is when you are listening to annoying music waiting for someone to help you.
• CDR (Call Detail Recording) - get precise and detailed information about any call made into or out of the system.
• More options (not an exhaustive list):
  • Wake up calls
  • Dictation services
  • Number Blacklisting
  • Call Forwarding
  • 3-way/4-way calling
  • Call Waiting
  • Directed Call Pickup (answer someone else's phone)
  • Blind Transfer/Attended Transfer
  • Channel Spy (listen in on calls)
  • Do Not Disturb
  • Fax Detection
  • Call Parking
  • Speed Dial