SIP is recommended for predictive dialer

Starting from release 7, SIP is the recommended VOIP service for Voicent Agent Dialer, especially when predictive dialing is used.

Skype has been until recently the VOIP recommended by Voicent, since SIP support is not available in release 6 and earlier releases. Though Skype is a good improvement over voice modem for predictive dialing, it has three major limitations:

1. Skype’s “unlimited” plan limits outbound calls to 50 calls per day
2. Audio quality for agent, especially remote agent, is not good
3. It is tedious to start multiple lines, especially on Widows Vista or later OS

With SIP support in release 7, and since SIP is the standard for VOIP services, you have a lot more choice for your VOIP service providers. You should be able to find a service plan that fits your situation. Most SIP calling rates are lower than Skype’s 2.1 cents per minute charge. In addition, Skype will support SIP soon and its SIP software is currently in beta.

Technically, there are major advantages of using SIP over Skype, even though both are VOIP services

When Voicent program interfaces with Skype, it must go through Skype’s COM interface, which has many limitations. To list a few – Voicent software cannot automatically sign out a Skype user and sign in with a different user; Voicent software cannot prevent the Skype window from popping up duing the call and cannot prevent Skype’s survey question from popping up; Voicent software cannot get all the error information from Skype. These limitations make it harder to even get the software to start. Some other limitations are not caused by the interface, but the way Skype is. For example, Skype cannot be started without a sound card, even though it is not used for Voicent software. For hosted server computers, you normally get a computer without a sound card and thus cannot use Skype in that environment.

When SIP is used, Voicent program does not need to go through an external interface – SIP is part of the Voicent program. Because of that, Voicent software has full control and does not need to deal with Skype’s interface limitations. The following are some major advantages of using SIP based VOIP service over Skype:

Better Audio Quality for Remote Agent

Skype’s audio channel requires more bandwidth and computing power, and is not suitable for remote agent. The audio quality usually suffers when a predictive call is transferred to an agent. With SIP, a better audio channel is used.

Technically, Skype uses TCP for its audio channel (when accessed through its COM interface) while SIP uses UDP. The difference is that TCP cannot tolerate lost IP packet, so the sender must resend the voice packet again. For real time voice communication, this delay means glitches and static in the voice. With UDP, the lost voice packet is tolerated and Voicent software will conceal the lost packet so to get the voice smoother.

Better Response Time for Screen Popup

When a predictive call is made, the audio needs to be analyzed to see if it reaches a live person. With Skype, there are long delays (in computer time) from time to time. You might hear someone say “hello” over the speaker. This is caused by the Skype delay and is not desireable. Without the early audio being redirected, Voicent program will not know the call is answered by a live human. This results dead air and most people will hang up the call.

With SIP, this audio is redirected as soon as possible. There will be some delay but should be much shorter than the delay caused by Skype.

Ease of Use

SIP does not have the limitations mentioned previously, as a result, SIP is much easier to use. For example, to start multiple lines, simply specify how many lines you want to start with a given SIP account, the gateway will take care of the rest. There is no need to switch to difference Windows account just to manually start a line.

Better Scalability

Each Skype line/instance requires 60M of memory. For a 32-bit operating system, it can easily reach the 4G total physical memory limitation. Normally, it cannot be used for more than 30 lines. With SIP, the additional 60M memory per line is no longer needed.

Switch to SIP

In summary, we see no reason to use Skype for predictive dialing for release 7 and later. Click the link to see more information about using SIP for Voicent.