Iridium SMS Features (and significant limitations)

  • The Iridium network supports two way SMS text messaging. But it's still a bit creaky...
  • 160 characters per message (newer Iridium 9555 may support long SMS..?)
  • Some equipment has limitations on sending/receiving (see section below)
  • Messages stored until delivered, up to 8 days
  • Subscribers pay only for outgoing SMS messages, incoming messages are free

Limitations of SMS to/from Cell(Mobile) Phones

  • Send/receive SMS between Iridium subscribers reliably
  • Send/receive from e-mail addresses reliably
  • Send from Iridium to most normal cell phones reliably
  • Replies from a cell phone to an Iridium handset are very operator dependent. It works for most US operators and a few european operators (hoping this situation will improve). Try it and see - if it works once it will usually work reliably with that operator
  • Note: You can send SMS messages for FREE to an Iridium handset using the Iridium website: (largely overcomes the limitations described above)

Specific Iridium Equipment Limitations

  • All units can receive SMS text messages
  • The original Motorola 9500 unit cannot send SMS messages (at all)
  • The fixed install Skanti/Sailor/Eurocom units are limited in that can only send/receive messages using a computer, not using the handset. The 9522-P/TP units are not affected, this is just a limitation of the handset on the Sailor handsets.
  • Some very early Motorola 9505 units did not have the capability to send SMS messages (upgrade to firmware Version LAC0307 or later)
  • Most units are limited to 160 character messages, but the latest Iridium 9555 appears to have some support for long SMS messages

Send an SMS message to an Iridium phone from an email account:

First Configure the Phone!

Configure Iridium Service Center Number!

  1. Enter the Iridium phone’s email address in the "To:" field of the email client. The email address is the Iridium phone number followed by "".
    Example: Iridium number is 8816 123 45678, then email address to send SMS is
  2. Type the message and then send it. The SMS message will be limited to 160 characters.

Send an SMS message to an Iridium subscriber from the Iridium website:

  1. Go to
  2. Enter the full phone number of the Iridium phone in the "To:" field.
  3. If a reply is desired, enter in an optional reply-to address.
  4. Enter the message and press "Send Message". The Iridium handset displays "Message Sent", which means that the message was successfully delivered to the Iridium SMS Center.
  5. The Iridium SMS Center will then attempt to deliver the message to the email account or Iridium subscriber. The delivery may fail if the email account is invalid or if the Iridium subscriber does not turn on his phone for 8 days or more. No additional notification is sent back in the case of delivery failure.

SMS between Iridium Subscribers (ISU to ISU):

From the keypad of the 9505/9555 phone:

  1. Select the menu option: "Message Editor"
  2. Enter your SMS message (as described in the 9505/9555 phone User’s Guide)
  3. Select "OK"
  4. Select the menu option: "Send Message" (as described in the 9505 User’s Guide)
  5. Enter either 00 <phone number> or + <Iridium phone number>
  6. Select "Send Message"

SMS from Iridium ISU to an Iridium Pager:

To send an SMS to an Iridium pager, it must be sent as an email. From the keypad of the 9505 phone:

  1. Select "Message Editor"
  2. Within the body of the message, enter the destination email address, followed by a blank space, then followed by the body of the message.
    Example: (space) body of message
  3. Select "Send Message"
  4. Enter one of the following: +*2, or 00*2, or *2
  5. Select "Send Message"

Replying to an Iridium SMS:

From the keypad of an Iridium phone:

  1. Select "Received Messages"
  2. Select your message
  3. Select "Reply To Sender"
  4. Enter the text of your reply
  5. Select "Send Message"
  6. You will be asked to enter the destination number with the originator’s phone number pre-populated as the destination number. If the pre-populated destination number is not the desired number, then enter the correct number.
  7. Select "Send Message".

Send SMS message from Iridium phone to email account

  1. Press the Envelope Key on the 9505 handset - Press the Menu key on the 9555 and scroll to Messaging.
  2. Use the Scroll Key to select the "Message Editor". Press the OK Key.
  3. Enter the destination email address, e.g.
    (Note: To get the "@" symbol, press the "1" key seven times.)
  4. Enter a blank space by pressing the # twice or down arrow on the Scroll Key twice.
  5. Enter body of the message. Press the OK Key.
  6. Select "Send Message" by pressing the OK Key.
  7. When the Iridium phone asks for the destination number, enter one of the following: +*2, or 00*2, or *2, then press the OK key.
  8. The Iridium phone will display "Sending Message" for a few seconds and then display "Message Sent", if the message was delivered successfully to the Iridium SMS center.

Replying to an Email Message via Iridium SMS:

From the keypad of the Iridium phone:

  1. Select "Received Messages"
  2. Select your message
  3. Select "Reply To Sender"
  4. The body of the reply message will automatically include the originator’s email address, but you can also overwrite this address.
  5. When "Send Message" is selected, "+2*" will be automatically added to the destination number field.
  6. Select "Send Message".