# GPRS - maintaining link

**URL:** <https://forum.sierrawireless.com/t/gprs-maintaining-link/3146>\
**Category:** Open AT\
**Created:** [April 21, 2009, 4:30pm UTC](https://forum.sierrawireless.com/t/gprs-maintaining-link/3146 "2009-04-21T16:30:10Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![BenFT01](https://avatars.discourse-cdn.com/v4/letter/b/73ab20/32.png) [@BenFT01](https://forum.sierrawireless.com/u/BenFT01)\
**Post date:** [April 21, 2009, 4:30pm UTC](https://forum.sierrawireless.com/t/gprs-maintaining-link/3146/1 "2009-04-21T16:30:10Z")

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I have an app running on an FSU which uses SMTP over GPRS. It all works fine. I use a flow to set up the connection with wip\_bearer\_open. The under lying library software gives trace outputs [GPRS]: GPRS EVENT: (event code - 27 for attached, 28 for disconnect etc). The library software seems to check for service every 15 secs or so. Does it send any test data to check the link, therefore incuring service costs, or can it do via some handshaking with the GPRS service? I just want to check if this always on implementation is reasonable for a 24/7/365 application, and not going to be running up bills.

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**Author:** ![Madouc](https://avatars.discourse-cdn.com/v4/letter/m/b782af/32.png) [@Madouc](https://forum.sierrawireless.com/u/Madouc)\
**Post date:** [April 22, 2009, 8:50am UTC](https://forum.sierrawireless.com/t/gprs-maintaining-link/3146/2 "2009-04-22T08:50:33Z")

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i personally doubt that is sends data. but i’m not sure though

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**Author:** ![BenFT01](https://avatars.discourse-cdn.com/v4/letter/b/73ab20/32.png) [@BenFT01](https://forum.sierrawireless.com/u/BenFT01)\
**Post date:** [April 22, 2009, 1:48pm UTC](https://forum.sierrawireless.com/t/gprs-maintaining-link/3146/3 "2009-04-22T13:48:11Z")

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I would hope not, but some mobile devices do, hence checking.

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**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\
**Post date:** [April 22, 2009, 2:26pm UTC](https://forum.sierrawireless.com/t/gprs-maintaining-link/3146/4 "2009-04-22T14:26:19Z")

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Without actually tansferring some data, you can’t be sure that the entire link is still up.

☹

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**Author:** ![BenFT01](https://avatars.discourse-cdn.com/v4/letter/b/73ab20/32.png) [@BenFT01](https://forum.sierrawireless.com/u/BenFT01)\
**Post date:** [April 22, 2009, 2:38pm UTC](https://forum.sierrawireless.com/t/gprs-maintaining-link/3146/5 "2009-04-22T14:38:19Z")

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I suspected it might have to do this. The costs would be low but have to be accounted for. ☹  
With mobile devices, people have been caught out when going abroad with GPRS active, and on their return get a huge bill as the service providers charge alot for data services abroad. 😮