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Thomas Han

May 23, 2016

Review of Grandstream GXP2135

See our review of Grandstream GXP2135 VoIP phone for businesses.

Telzio has been following the progression of VoIP phones from Grandstream, and its latest release of the GXP2135 does not disappoint. On the market since February 2016, the Grandstream GXP2135 business VoIP phone is the new and improved model from the GXP2000-series, offered at a reasonable price point and with enhanced features.

Established in 2002, Grandstream Networks is the younger maker of VoIP products for business and enterprise compared to Cisco and Polycom. Its newer designs and lower prices have made it a favorite among small businesses. Despite their lower price point, Grandstream phones offer the feature set and quality fitting for high-volume call centers and enterprises.

Grandstream GXP2135 Key Features

In addition to the standard features – hold, transfer, and call waiting, the GXP2135 combined with Telzio’s business VoIP service delivers enhanced features including call parking, hold music, call forwarding, intercom and paging.

Other featured highlights include:

  • 8 lines
  • 4 SIP accounts
  • 32 busy lamp field (BLF)/speed-dial keys
  • 2.8-inch color LCD
  • HD audio
  • 4-way conferencing
  • Power-over-Ethernet
  • Built-in Bluetooth

Compared to the earlier model GXP2130 that had 4 lines and only 8 BLF keys, the GXP2135 is sold at around the same price.

Business VoIP Phone Service

Grandstream VoIP phones work seamlessly with Telzio’s business VoIP service, from enhanced features, to easy setup, to high definition call quality.

SIP Accounts

The GXP2135 can handle up to 4 SIP accounts, meaning the phone can be registered with up to 4 phone numbers, or extensions.

Telzio is unique from all other VoIP providers in that it offers unlimited extensions, aka users, so essentially, a company can have one main number and add extensions for all employees to the phone system at no additional charge.

The cost benefit of unlimited users for small businesses is substantial, since the only added cost would be for any actual usage not covered under the free minutes in a plan. But with Telzio, plans can be changed at anytime online, making it easy to scale up or down as needed.

Simultaneous Calls

With 8 lines, a user can be on 8 active calls simultaneously, and when all lines are busy, callers will still never experience a busy signal. Telzio allows an infinite number of simultaneous calls on the same number without the need for additional phone numbers (aka rollover lines) to handle the calls. When all lines on a phone are occupied, Telzio can be customized to send callers to a queue, voicemail, or other action.

Setup & Interface

Telzio provides an easy setup process for Grandstream phones directly through Telzio’s web dashboard and the phone’s display. With Telzio’s step-by-step guides and intuitive design, even non-technical users can configure an IP phone to work with their VoIP service. Alternatively, Telzio offers a pre-configuration service so phones arrive ready for calling.

Overall, the design, cost, and usability of the new Grandstream GXP2135 is a win. I’ve replaced the Grandstream GXP2140 on my desk to the GXP2135. The audio quality is crystal clear with no delays even when calling internationally. The phone also has an updated look, making it more sleek and modern, which is always a plus at a design-centric tech company like Telzio.

For help on choosing the right VoIP phone and plan for your business, contact us at