CODEWITHSUNDEEP
commandat-commandgprsapn
user3771738
user3771738

Reputation: 19

GPRS AT Command CGDCONT - Do I really need an APN?

I am developing embedded firmware to communicate with the Multi-Tech's MTSMC-H5 GPRS Modem. I am unclear the use of AT+CGDCONT command. In the H5 modem's Reference Guide, it states the command format is

>AT+CGDCONT=[<cid>[,<PDP_type>[,<APN>[,<PDP_addr>[,<d_comp>
>[,<h_comp>[,<pd1>[,…[,pdN]]]]]]]]]
>...
><APN> Access Point Name. String parameter that is a logical name used to select the
>GGSN or the external packet data network. If the value is empty (“”) or omitted,
>3GPP TS 27.007 AT COMMANDS then the subscription value is requested.
>...

What effect would that be if I leave the APN field blank? It seems I can connect to the cell network while leaving the APN field blank. I tried several SIM cards and they all seem to work without specifying the APN field. However, I'd like to know for sure that what I do is appropriate. Because I have very limited UI capability (no real keypad on the device that the modem is attached to), it is highly desirable if an end user does not have to enter any APN information.

Upvotes: 1

Views: 2898

Answers (1)

user1725145
user1725145

Reputation: 4042

The APN was probably stored on the SIMs that you used. In most cases, it will be OK as you found out. There are a few edge cases where you might run into problems, such as an APN changing (rare), or arrangements between individual operators, or between operators and certain customers.

Even these cases can be mitigated by some operators as they automatically correct a wrong APN (APN redirection).

Note that this is not behaviour that is mandatory under the 3GPP standards, so it may vary from operator to operator.

Upvotes: 3

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