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7 Disadvantages of TDM PBX vs. Cloud-Based Communications

7 Disadvantages of TDM PBX vs. Cloud-Based Communications

Whoever said "if it isn't broken, don't fix it" wasn't talking about an outdated TDM PBX (Private Branch eXchange).

Sure, your TDM (Time Division Multiplexers) PBX may be working today. But will that be the case tomorrow?

There are any number of factors that can cause an old-school telephone system to fail when you need it most. They include damage to the equipment on premises, power problems at your site, cut cables in the phone room by phone company techs, or parts that fail because of the length of time they've been in use.

If your system does stop working, how long will it take to get a technician on site who are trained on legacy equipment?

Few organizations can afford the risks to their reputation associated with something that usually "just works". You wouldn't hire a customer service representative who only occasionally answers their phone. You can't afford to sell a product that is good some of the time.

Why would you gamble on the reliability of your phone lines?

In this article, we’ll talk about the glaring differences between TDM phones and hosted voice, and why TDM can present more business risks than you ever thought possible.

Quick Definition: What is TDM PBX?

A TDM PBX is a type of private branch exchange technology, which consists of traditional switching technology and relies on service connectivity over copper wires to a plain old telephones (POTs) vendor. TDM systems are proprietary, and require organizations to purchase "boards" from the vendor to extend functionality or perform intercom and analog extensions.

Unlike hybrid PBX systems, TDM technology pre-dates the Internet and cannot support IP-based telephony (VoIP). It also cannot be integrated with different technological solutions. It's based on circuit-switched technology that dates back to the early 20th Century rather than the packet-switched technology that defines the Internet.

TDM has been used for generations, and generally represents a reliable method of business voice communications. However, as organizations move to more agile and integrated modes of business communications, organizations are realizing reliability, cost savings, and interconnectivity gains by switching to cloud-based phone service.

To learn more, we recommend TDM vs. SIP: Which is Best?

7 Risks to Your Business with TDM Phones

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1. Difficulty adding new phone lines

TDM relies on hardware and phone lines to carry your voice traffic. If your organization needs to add new phone lines, the effort required to extend your PBX to cover more users can be fairly extensive. Depending on your provider and resources, you may need to wait over a month for the cabling work required to support TDM connectivity to be completed.

In contrast, cloud-based phones can be scaled up and down effortlessly. As long as you have handsets and connectivity, all it takes are a few simple changes in your administrative portal, or a call to your full-services unified communications as a service (UCaaS) vendor to get new hires set up with a phone line.

2. No mobility

With TDM technology, your phone lines extend exactly as far as your desk, or rather, exactly as far as the cord that connects the handset to the wall. TDM technology was designed for the offices of yesterday, where employees almost always "stayed in place".

Today, employees may move throughout the office with mobile devices and laptops to collaborate, or work remotely. TDM technology doesn't integrate or provide mobility, meaning that employees will need to be furnished with a separate mobile device if they're not close to their desk.

3. No integration

TDM technology was extensible when it was developed; you could purchase hardware to support intercom functionality and operate internal switchboards for transferring calls to employee extensions. However, it isn't designed to integrate into today's business communications ecosystem; which can consist of a complex series of applications.

Hosted VoIP treats voice calls as data, which allows your phones to be integrated with digital mailboxes, fiber-optic internet connectivity, data services, and a host of other platforms. A phone call from a customer may populate your customer relationship management (CRM) tool, keeping your sales and customer service teams in-the-loop and enabling your business to provide multi-platform support. In a world where customers and employees make little distinction between phones, chat, and email, a phone system that can't be integrated with your communications technology represents a continuity risk.

4. Difficult Updates

TDM technology doesn't require frequent updates. You won't need to download software patches, or perform frequent calibration. However, making changes to meet your businesses' needs isn’t always easy.

Purchasing new hardware to extend your TDM can be costly. Depending on your internal resources, you may need to schedule a time with your phone service vendor to perform cabling updates. TDM technology is frequently proprietary, which means that your ability to shop around for the best prices and add one vendor's solution to another's TDM cabinet is significantly limited.

5. No Multi-Location Functionality

For multi-location organizations, Hosted phone service and UCaaS have enabled a centralized communications suite. Even if your employees are in multiple buildings, you're able to access the same phone lines and communication tools via the cloud.

TDM doesn't offer multi-site integration. If your organization wants to add a new building, you'll need to purchase an entirely new TDM infrastructure, as opposed to receiving an extension of the same phone systems and communication apps from your UCaaS vendor via fiber-optic internet connectivity.

6. No Remote Fixes

When a TDM system goes down, there is no telling when it will be back up again. Firms who are lucky to have an expert telecommunications specialist on staff may be up and running after adjusting the hardware or programming of their TDM system. If a cable has been cut or there's another large-scale issue, however, you may be stuck waiting for your phone company's service technician to show up.

In many cases, cloud-based phones can be fixed from a remote location. Your internal administrator has the power to perform basic troubleshooting from a simple web-based portal - even if they're not on-site. Selecting a vendor with 24/7/365 expert customer assistance and business continuity planning improves your access to a fast resolution.

7. Single Point of Failure

TDM phone lines are a single, centralized solution for voice communications. If the wires are damaged or subject to interference, you're not able to switch to backup routes for your phone traffic. If your TDM hardware fails, you need to order a replacement. There's a series of interconnected pieces, which need to all work correctly in order for you to have voice service.

In contrast, VoIP connectivity is built for durability. With dedicated fiber-optic internet connectivity, you won't be subject to voice quality concerns when public demand for bandwidth spikes. Your fiber can't be easily impacted by inclement weather, interference, or other forms of damage. In the rare case you do lose fiber connectivity, your employees can continue working and communicating with customers thanks to mobile failover, or the ability to receive calls via a mobile app.

Can You Absorb the Risks of TDM PBX?

TDM carries the benefit of being a familiar technology that's been tested over the course of decades. However, few businesses can afford the risks associated with a single-point-of-failure for voice communications; to wait for their phone company to perform cabling work every time a significant change is needed; or voice communications that don't integrate with mobile devices or other cloud-based apps.

Your customers don't accept "usually" or "almost" as an acceptable level of service. If voice is imperative to your business, selecting cloud-based phone service can reduce the risks that your phones go unavailable for long periods of time or you're stuck waiting to scale your system.

To learn how quickly you could save by switching from TDM to VoIP, we recommend The Essential Guide to Phone System Pricing.

Tom Collins
Post by Tom Collins
May 18, 2017
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.