In 2015, Iridium launched a Push-to-Talk service.  Iridium PTT immediately received the "Top Emergency Response Innovation" award at SATELLITE 2016.  For more on that see the Mobile Satellite Users Association 2016 Mobility Satellite Innovation Awards.   Iridium PTT uses mobile handheld satellite phones instead of the bulky terminals currently used by Light Squared (MSAT) or Inmarsat BGAN push-to-talk services.  We will provide more information about Inmarsat BGAN based PTT services in a future article.

Who will benefit most from Iridium PTT?

Like cellular-based push-to-talk services, Iridium PTT is intended for groups of users not single individuals.   For this reason, the main beneficiaries of Iridium PTT will be corporations or government organizations with high volumes of internal communications.  Instead of paying for costly Iridium telephony-mode calls which typically cost between $1.09 and $1.29 per minute, unlimited PTT communications are available amongst an entire group of people for a flat fee of under $120 per month per handset.*

In order to use Iridium PTT services, a customer must activate at least two Iridium PTT devices and one Talk Group.   The Talk Group specifies the area within which an Iridium PTT device can engage in PTT communications.  If your application is in North America, you may be eligible for a free Talk Group.   For standard pricing, click here.

Interconnecting Iridium PTT phones to portable radios

It is straightforward to interconnect groups of portable radios or existing MSAT equipment with groups of Iridium Extreme PTT satellite phones.   The interconnect solutions are affordable.  Outfitter Satellite will be pleased to arrange a demonstration to your organization.  Just tell us the model or type of VHF/UHF portable radio that your group is using.  Please call 615-889-8833 for more information.

Can Iridium PTT phones also call regular phone numbers?

The Iridium Extreme PTT handset can be switched from PTT mode to telephony mode.  Unlike PTT mode, telephony mode lets you can make phone calls to fixed or mobile phone numbers.   In addition to phone calls, the Iridium Extreme PTT supports the following telephony services:

  • 2.4 kbps data calls
  • SMS messaging with an email-to-text conversion feature
  • GPS-enabled emergency messaging via a single-touch SOS button feature
  • GPS tracking via SMS messaging
  • GPS tracking via LBS (location based services).

Iridium PTT Talk Groups

Various Talk Group sizes are available.  A Small Talk Group is about the size of Indiana.  A Medium Talk Group is about the size of Arizona.  The Large Talk Group is about the size of Texas.

For groups that are operating in diverse areas, it is important to realize that the Talk Groups can be divided into as many as 10 different regions anywhere on earth.  For example, you could cover an area around Washington DC with one region and a second area in Maine -- wherever people in Talk Group are expected to operate.

To make it easy to configure your Talk Group, a password-protected web interface called the PTT Command Center lets you sketch out your Talk Group's boundaries.  Circles, rectangles, and other shapes are available.  Also, the PTT Command Center lets you assign which Talk Groups are attached to each individual Iridium PTT device.

Up to 15 Talk Groups can be assigned to a single Iridium PTT phone, though that phone can only participate in one Talk Group at a time.  The Iridium Extreme PTT handset user, can switch between allowed Talk Groups directly from his or her handset.

North American Medium Talk Group Promotion for Iridium PTT

Iridium is currently* offering up to three free Medium Talk Groups for users in Canada, Mexico, and much of the United States.  This includes all 50 states and the U.S. Territories of Puerto Rico and the U.S. Virgin Islands. The following eligibility requirements must be met:**

  1. The customer’s billing address must be in the North America Zone.
  2. The boundaries of the Talk Group must be strictly kept inside the North America Zone.
  3. Three active PTT devices are required to be eligible for a free Medium Talk Group monthly fee.  Six active PTT devices qualifies the customer to be eligible for two Medium Talk Groups.  Nine active PTT devices qualifies you for three Talk Group monthly fees.

PROs of Iridium PTT

  • Iridium PTT uses a small handheld phone, the Iridium Extreme PTT.   By comparison,   Inmarsat BGAN and MSAT have much bulkier equipment designed for vehicle-based applications.
  • Iridium PTT is available globally unlike Inmarsat BGAN and MSAT.
  • Each Iridium PTT customer group can configure the boundaries of its talk groups on the fly using a password-controlled web interface.
  • Unlimited PTT usage is available for a flat monthly fee.  By comparison,  Inmarsat BGAN based PTT services consume standard IP data services for which there is a usage cost.  In other words, the more Inmarsat BGAN based PTT communication you use, the more it costs.

CONs of Iridium PTT

  • Iridium PTT service plans have more expensive monthly fees than Light Squared (MSAT) plans.  However, Iridium is currently offering free Medium Talk Groups for eligible users in the North America Zone.
  • Iridium PTT will drop calls more often than Inmarsat BGAN services.  Fortunately, when Iridium launches its second generation Iridium NEXT satellites (expected in early 2018), Iridium call drop rates are expected to improve dramatically.

About the Iridium satellite network and Outfitter Satellite

Iridium launched its original satellite network eighteen years ago with 66 low earth orbit  satellites.  This gave the world its first global voice and data mobile service.   Beginning in January 2017,  Iridium began launching its second-generation satellites.  The second generation Iridium NEXT satellites offer much faster data speeds (see our Iridium NEXT review article).

Outfitter Satellite is a company in Nashville Tennessee that was selected as one of the first Authorized Iridium PTT Resellers.   In addition, Outfitter Satellite also rents  Iridium and Inmarsat satellite phones and terminals.


*All promotions, fees, pricing, rates, terms and conditions mentioned in this article are accurate as of the time of the original writing of this article but are subject to change without notice.   USF fees, and other fees and taxes apply to this service.   There is a monthly fee for each Iridium PTT device.  Also, there is a separate monthly fee for each Talk Group.  If the user chooses to use telephony-mode services, usage costs will apply.   There are no usage costs other than the fore mentioned monthly fees for Iridium PTT.   Unlimited PTT communications are included in the Iridium PTT device's monthly service fee.

**Iridium occasionally audits compliance with the terms of this promotion, and the customer must agree to pay the Talk Group's monthly service fees starting from the first of the month on any non-compliance is identified in such audit.