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TDM vs. SIP: Which is Best for Business?

TDM vs. SIP: Which is Best for Business?

Businesses that are looking to advance or scale their phone systems are facing a tough decision today. 

For over 3 decades, Time-Division Multiplexing (TDM) has been the reliable standard. And while TDM has providing loads of value for businesses, the future is owned by the newer SIP (Session Initiation Protocol) technology.

It allows for more innovative implementations and has numerous advantages over TDM systems.

Still, TDM is here to stay for the immediate future, until SIP implementations become so cheap that companies no longer have a logical choice but to migrate to the newer technology.

This brings up a common question: should companies should stay with TDM or make the jump to SIP.

SIP vs. TDM: Which Is Best?

The truth is, deciding which one is better depends on your company. From a technological perspective, SIP is obviously better. There are just so many advantages of treating voice as data, from both a usability and technical standpoint.

The real question that must be answered is, which one is best for you?

For some companies, sticking with TDM technology may be the best choice. If budgets are low, and if telephone usage is a low priority for your company, sticking with the old technology is a cost-effective, low-maintenance way to go. However, if your phone system is imperative to company success, upgrading to SIP can make a lot of sense over the long term. Just make sure you have enough bandwidth to support adding phone service delivered via SIP to the other traffic you generate over the Internet.

One of the greatest benefits of SIP is the ability to add services like our nation-wide business wireless, Microsoft Teams Calling, and more. If you're interested in seeing what a premier telecommunications provider can do for your business phone services, contact Atlantech today

Advantages of SIP Over TDM

TDM is a relatively old technology, relying on telco switch signaling to make phone calls work. It's a brilliant system, which is why it's been used for more than 50 years. But when it was invented, the Internet wasn't even thought of yet. Now with a hyper-connected world, the ability to transmit data so quickly has introduced exciting alternatives to traditional phone systems.

SIP Costs Less Than TDM

TDM relies on phone lines and technical equipment to make phone calls happen. SIP calls are transferred over a single IP path (or multiple paths if you've engineered some redundancy into your network design), along with data and video signals.

Because everything becomes data, the cost of infrastructure goes way down as you can leverage the same wiring and network equipment for both voice and data traffic.

The physical hardware required for SIP is also much less than with TDM as you're using Ethernet rather than specialized Telco interfaces. Gone are the days when you'd need to purchase HSSI cards for a DS-3 that could cost thousands of dollars.

SIP doesn't require a specialized, telco gateway nor the installation of phone circuits from the ILEC. Instead, all you need is broadband internet connectivity.

SIP Has More Flexibility

Due to a reliance on data transfer, as opposed to physical equipment, SIP has more flexibility, both in implementation and usage. Installing and upgrading SIP trunks is something that can be done quickly and easily without the purchase of expensive new hardware. For instance, if you have 23 PRI lines and want to go to 27 lines, you'll have to order a new card for your PBX and have a second PRI installed. Circuit install can take as long as 30 - 45 days. Turning up more call appearances on an SIP trunk can be done self-serve through a web interface or simply by opening up a ticket with your carrier.

SIP Is Easier to Manage

Because SIP phone service is much like broadband Internet connections, troubleshooting problems becomes a simple process without the need to call in outside technicians to check hardware. IP hardware has a much longer lifespan than TDM, so investments made into the technology bring a higher ROI at a lower price. And, it can be leveraged across both your data and voice networks... as it's been converged into one!

SIP Extends Your Office

Because the signal is controlled like data, phone numbers no longer are determined by the location of equipment. A company headquartered in New York can have a local number for satellite offices in Los Angeles and Dublin.

Phone calls can also be rerouted easily regardless of the location of the receiver. In this way, employees across the globe can interact with phone calls like they were in connecting cubicles. Being able to connect from anywhere, even while on vacation, is another huge advantage of employing SIP technology.

SIP Is More Reliable

There are more advantages to SIP than just cost and features. SIP is more reliable than TDM for a few reasons, mainly the lifespan and operative simplicity of the equipment. But there are redundant backups to ensure your phone system doesn't face any downtime from hardware failures.

Making a Seamless Transition from TDM to SIP

Let's imagine you decided to switch from TDM to SIP. Here are four things you will want to keep in mind as you begin planning your transition. 

1. Assess Critical Services

Prior to transitioning, assess vital services dependent on your existing TDM infrastructure, such as voice communication, fax lines, point-of-sale systems, and alarms. Understand the impact of migrating to SIP trunking to mitigate disruptions effectively.

2. Optimize Traffic Routing

Plan how to route traffic from traditional TDM applications to SIP trunking. Ensure smooth call handling and integration with current systems. Prioritize essential functions like fax lines and point-of-sale systems for uninterrupted connectivity throughout the transition.

3. Select a Supportive Provider

Opt for a SIP trunking provider with robust support options for seamless transition assistance. Seek proactive monitoring, remote management, and on-site support for prompt issue resolution, minimizing downtime.

4. Perform a Proof of Concept:

Prior to full adoption, conduct a proof of concept to test SIP trunking feasibility and efficacy. Implement on a smaller scale to assess performance, compatibility, and suitability. Refine strategy based on insights gained, addressing challenges preemptively.

How to Evaluate Providers for your TDM to SIP Transition

When transitioning to SIP trunking, selecting the right service provider is crucial. Here's what you should look for and request from potential vendors:

  • A solid track record of successful TDM to SIP transitions. Ask for specific examples of their work.
  • Responsive support that won't leave you high and dry.
  • Their level of assistance during the transition, including planning and troubleshooting. You want to be very clear about is and isn't included in their offering.
  • If they will conduct a proof of concept, which can offer valuable insights into feasibility.
  • If they will set up a test environment and address any issues before full deployment.


TDM vs. SIP: Which Is Best For Your Needs?

Addressing this question again comes down to your needs. If basic phone service is all you need, and your company doesn't have a large reliance on phone service, having a TDM system in place may be the best option. If phone service, and the innovative ways to implement it over IP, is something that can add value to your company, customer service, and business processes, you may need to make the leap to SIP.

We recommend talking to a professional to get a needs analysis completed before you decide to buy a phone system or service. This way you will know you are getting exactly the service and functionality you need to help your business thrive. You can contact the professionals at Atlantech today to start mapping out the ideal phone system for your business.

Tom Collins
Post by Tom Collins
May 14, 2024
Tom is the Director of Enterprise Sales & Marketing for Atlantech Online. He has over 20 years of professional experience in the Internet Service Provider industry and is known for translating technology into positive results for business. A native of Washington, DC, a graduate from University of Maryland (degrees in Government & Politics and Secondary Education), Tom is also a five-time Ironman finisher.