# HL7810 callbox connection problem

**URL:** <https://forum.sierrawireless.com/t/hl7810-callbox-connection-problem/35701>\
**Category:** Legacy HL Series\
**Tags:** debug\
**Created:** [January 6, 2026, 1:34am UTC](https://forum.sierrawireless.com/t/hl7810-callbox-connection-problem/35701 "2026-01-06T01:34:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jerry.li](https://avatars.discourse-cdn.com/v4/letter/j/df788c/32.png) [@jerry.li](https://forum.sierrawireless.com/u/jerry.li)\
**Post date:** [January 6, 2026, 1:34am UTC](https://forum.sierrawireless.com/t/hl7810-callbox-connection-problem/35701/1 "2026-01-06T01:34:15Z")

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Hi,

The HL7810 module disconnects after approximately 20 seconds of connection to the callbox.  
Since it’s just a simple connection without transmitting data, we’re unsure if this is the cause.  
We’ve tried two modules with the same issue.  
Both modules connect to the base station normally using a carrier’s SIM card.  
Is there any way to make the module recognize this as a genuine connection and maintain the connection?  
We’ve confirmed that the module is not in DRX or PSM mode

Best Regards,

Jerry Li

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<div class="post-metadata">

**Author:** ![jyijyi](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.sierrawireless.com/jyijyi/32/4766_2.png) [@jyijyi](https://forum.sierrawireless.com/u/jyijyi)\
**Post date:** [January 6, 2026, 1:43am UTC](https://forum.sierrawireless.com/t/hl7810-callbox-connection-problem/35701/2 "2026-01-06T01:43:22Z")

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are you testing NBIOT or LTE-CatM?

Does the cause\_type in +CEREG give any indication?

Have you tried other module like WP7702 and see if this is callbox problem?

BTW, is there any improvement when disabling eDRX by AT+CEDRXS?