Globalstar Product Management – Technical Support

Data-capable Globalstar User Terminals are all equipped with the Silent Retry feature for Packet Data Connections.  This includes the following Globalstar products: GSP-1720, GSP-1700, GSP-1620, GSP-1600 and GSP-2900.

Wireless communications are subject to far more performance impacting conditions than wired communications.  When a user’s computer or a remote data collection computer system issues the ATD#777 dialing command to connect to the internet, the Globalstar terminal will continuously reissue the connection request until the Silent Retry Timeout expires.  

The default value for Silent Retry Timeout is 2.5 minutes (150 seconds), and can be reset using the AT command, ATS777=n where “n” can be any value in the range 0-255

Important Effects of Silent Retry

Increased Ease and Success of Packet Data Connections:

1. 1. The success rate for any particular packet data connection attempt is no longer dependent on transitory variables such as the momentary status of local interference, physical sky blockage, etc.  Instead, internet connections are much more likely to succeed with the use of a simple dialing command rather than having to program a complex re-dialing procedure into a remote computer.  
   2. The retry algorithm for the connection attempts is tuned to the characteristics of the Globalstar link and is therefore very effective and rapid.

Variable Connection Times

1. 1. A side effect of the Silent Retry Timeout is that when issuing the ATD#777 command, it can take varying amounts of time to get the link established
   2. It is important for hardware integrators to understand the reason for the variability, and to use the Silent Retry feature to their advantage, rather than manually terminating any connection attempt that takes longer than a pre-set time to get established.

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Additional keywords:  1720, sdvm