Entering the Iridium SMS Service Center Number
Free Iridium SMS Messages
Before a subscriber can send an SMS message from the Iridium system, the Iridium SMS service center number must be stored on the SIM card.
To store the Iridium Service Center Number:
Service Center on Iridium 9500/9505/9505a/9522 Handsets
- Press the Envelope Key on the handset.
- Use the Scroll Key to select the ‘Message Settings’ option. Press OK.
- Use the Scroll Key to select the ‘Service Centre’ option. Press OK.
- Enter 00881662900005 or +881662900005. Press OK.
- The phone will momentarily display “Completed”.
Service Center on Iridium 9555 Handsets
- Press the Menu Key on the handset.
- Use the Scroll Key to select the "Messages" option. Press Select.
- Use the Scroll Key to select the ‘Settings’ option. Press Select.
- Use the Scroll Key to select the ‘Service Centre’ option. Press Select.
- Enter 00881662900005 or +881662900005. Press OK.
- You need to follow the Iridium Voicemail setup instructions in order to have reliable message delivery - this is because the SMS messages are only sent when the satellite constellation knows where you are, eg making a call, or voice mail check
- This procedure needs to be performed once per SIM card because the number will be stored on the SIM.
- This procedure is valid only for Satellite Series 9505 handsets that have the current software version, which is LAC0307.
- To determine the software version of any 9505 handset, go to the initial screen and press *#91#. The following software for 9505 handsets has been released in the past: LAC0103, LAC0105, LAC0107, and LAC109G (the most common version). 9505 handsets with older software can be reflashed by your Iridium service provider. Only one reflash is required; it is not necessary to incrementally reflash, i.e., reflash from LAC0107 to LAC109G then finally to LAC0307.
SMS messages are limited to 160 characters. Messages that are longer than 160 characters will be truncated to 160 characters. The 160 character limitation applies to MO (Mobile Originated) and MT (Mobile Terminated) messages whether originated from an email service, from Iridium’s website, from other cellular networks, or from another Iridium subscriber.
Character Set Supported
Iridium Short Message Service (SMS) supports the English Alpha Numeric characters only (capital & lowercase). These characters comprise the following:
0 1 2 3 4 5 6 7 8 9. ? ! , @ & : " ( ) ' x * / = > < #
Message Delivery Attempts
Once the Iridium network receives an SMS message, it will immediately attempt a delivery. If the destination phone is not available; the network will attempt delivery according to the following schedule:
- 2 retries every 2 minutes
- 2 retries every 5 minutes
- 6 retries every 10 minutes
- 12 retries every 4 hours
The total time span for delivery attempts is 2 days 1 hour and 14 minutes. After this retry schedule finishes, the message will wait in the message box until the ISU registers, which would cause the delivery of the message. If after 8 days the message has not been delivered to the recipient, it will expire and be deleted from the message box.
The end user can initiate delivery of SMS by manually registering the phone, by either placing a call or pressing the "up arrow" then the "8" keys.
Message Expiry Period
The user can change the SMS message expiry period via the “Expiry Period” option in the “Message Settings” menu. The default expiry period is 8 days, but can be set incrementally from one hour up to 24 hours, then 48, 72, 96, 120, 148, 164 and 192 hours.
SMS Interaction with Voice Calls
It is possible to create and send an SMS-MO (Mobile Originated) via AT commands during a voice call without interrupting the voice call. It is possible to receive an SMS-MT (Mobile Terminated) during a voice call without interrupting the voice call.
(Note: Theory and practice diverge somewhat and often if an SMS message is received during a voice call it can cause a degradation in quality for a brief period)
Maximum Number of Messages
Up to 30 messages can be stored on the SIM card. This can be any combination of received messages and outgoing messages, up to a total of 30 messages. When the limit is reached, no more messages will be delivered to the SIM card until some messages are deleted.
Maximum Frequency of SMS-MO (Mobile Originated)
- ISU to ISU: There is currently no maximum.
- ISU to email: There is currently no maximum.
- E-mail to ISU: The maximum number of SMS messages that can be sent from an e-mail account to an Iridium subscriber is 5 messages per 10 minutes per each originating email address.
- Iridium Website to ISU: The maximum number of SMS messages that can be sent from the Iridium website (or comparable websites) to an Iridium subscriber is 5 messages per 10 minutes.
Iridium charges for all SMS delivery attempts, whether it is a successful or unsuccessful delivery, at approx $0.40 US per message (for pre-pay airtime it's 6 seconds of airtime deducted). Charges are per-message whether the message contains 1 character or 160 characters.