When setting up a phone system these days, there are many ways to answer calls and transfer them around to best serve the caller with the right person to address the call.

History

In the late 1950s and early 1960s, there were only two types of line sharing available on telephone systems.  The lines were either shared on a switchboard or shared locally on a key telephone.  This inefficiency was a significant factor that gave rise to Centrex and PABX solutions in the 1970’s.

Today

Modern day telephone systems have many ways of answering and redirecting incoming calls.  This blog is going to address three of them:

• Call Transfer allows you to transfer a call to a particular phone, but someone has to be at the intended destination to answer and receive the call or have voicemail enabled. 
• Call Parking allows you to place a call on “hold” and then have the appropriate person retrieve the call from any telephone connected to the phone system.
• Shared Call Appearance (SCA/SLA) is a call presented on a line button and overhead speaker announces to the organization for a user to pick up Line 1 or Line 2 to retrieve the call. Anyone with the same line button on their phone can pick up the call.

Call Transfer

Let’s start with Call Transfer. Call transfer begins when anyone on the system answers a call.  This is typically an operator or receptionist who would take the incoming call, initiates the transfer to the desired extension and the call is connected to the desired party. Transfer can be initiated in different ways depending on the phone system or phone type. The most common way is using the “transfer” key.

The operation can be automated by a feature known as Auto Attendant or IVR (Interactive Voice Response). When an incoming call is answered by the Auto Attendant, you are given options on where you want your call to be sent by pressing the digits on your keypad. Once the system recognizes the digit(s) entered, it automatically transfers you to the desired destination.

Advantages of Call Transfer

• Relatively easy to use
• Quick and fast distribution of calls
• Can be done automatically by an Auto Attendant or IVR

Disadvantages of Call Transfer

• The desired party needs to be at the phone in order to pick up the call if AA/IVR is not available
• If the call is transferred to the wrong extension, there is no way of getting the call back immediately
• Cannot be used together with paging to announce the call before transferring

Call Parking 

Call parking can be thought of as a sophisticated way of holding a call.  Instead of holding a call on a particular telephone, the call is held in a shared location on the phone system. Any telephone on the system can park the call in this shared location by transferring the call to the Call Park extension.

For example, if the Call Park extension is 700, you simply transfer the call to extension 700. Most phone systems will allow programming of a feature button for Call Parking, thus allowing the feature to be activated by a simple press of the feature key.

The feature allows multiple calls to be parked at the same time and therefore you need to know where your call is being parked. After parking a call, the system will then display and/or announce the call park number where your call is parked, For example, the system might announce the number 701. Then the call can be retrieved from any extension on the system by simply dialing the call park number 701. If the call stays parked for too long without being retrieved, the system will automatically ring the extension that parked the call.

In many modern supermarkets and department stores, this feature is frequently utilized to get calls to different areas of a store by simply announcing over the PA system, “General merchandise please take the call parked on 701.”

Advantages of Call Parking

• Call can be announced and picked up on any phone on the system, which is especially helpful in a large organization with multiple floors or large square footage.
• Multiple types of telephones from digital to wireless to analog to IP can pick up the call simply by dialing a code.
• The call is returned to the extension that parked the call if no one picks up the call.
• The held call does not tie up a line on a telephone.

Disadvantages of Call Parking

• The person parking the call needs to remember the call park number to retrieve the call.
• The status of the held call does not show on the phone’s feature button or line key.
• Can be disruptive to the organization with overhead paging announcing calls to be picked up.

Shared Call Appearance 

Another common way to share lines and incoming calls is called Shared Call Appearance or Shared Line Appearance. In older telephone key systems, this feature is based on having dedicated line buttons on all the telephones in the system. They are usually labeled Line 1, Line 2, Line 3, etc.  The line button will indicate whether the line is available, ringing, on hold or in use. When a call comes in to Line 1, any phone with Line 1 button configured can pick up the call, hence the name Shared Line Appearance.

In modern PBX systems, fewer lines are shared by a larger number of extensions on the system. Telephones on the system no longer have keys dedicated to lines. However there is still a demand for the capability to have multiple extensions share the same call appearance, thus the name Shared Call Appearance.

The Shared Call Appearance (SCA) feature on a PBX system typically provides the following capabilities:

• Calls can be presented on multiple phones
• The SCA key provides visual indication of the call state
• Any phone on which the call is presented can answer the call
• If an SCA call is put on hold, any extension with the SCA key can retrieve the call 

Let’s use an example to demonstrate how the Shared Call Appearance feature works.

The phone for the receptionist can have multiple SCA keys, one for each department; while the different departments can have phones with just the SCA key(s) for their own department.

Advantages of Shared Call Appearance:

• Easy to pick up calls by simply pressing the SCA key.
• Visual indication of the call state.
• Calls can be announced before pick up.

Disadvantages of Shared Call Appearance

• Only telephone(s) with the corresponding SCA key can pick up the call.
• Buttons need to be dedicated for each SCA key taking up buttons that could normally be used for other features.
• Can be disruptive to the organization with overhead paging announcing calls to be picked up. 

Summary