adl_fcmSendData() returns the error value "-21"


I am using a Fastrack “M1306B” with “OpenAT 3.01” and Firmware “650a”.

Sometimes the function adl_fcmSendData() returns the error value “-21”.
But this error is not referred in my Help files.
The only thing to correct this problem is resetting the modem.

Anyone knows this problem ?


Hi mib !

Error -21 for adl_fcmSendData() is specified as ADL_FCM_RET_ERR_WAIT_RESUME (see adl documentation, “specific FCM service error code” chapter). That means the subscribed flow has no more credit left.

So the sending buffer for this flow is full… (i think it is 5 credits max)


I don’t know about v3.01 but, in the ADL User Guide for v3.03, there’s section 4 at the end of the document called Error Codes:

Section 4.2 lists Specific FCM Error codes:

So that’s your -21 8)


Thank you very much.
You are right, by having a new look on my sources “-21” stands for “ADL_FCM_RET_ERR_WAIT_RESUME”.

Normaly the credit will be released by receiving data with the handler “adl_fcmDataHdlr_f()”.
In case of timeouts this handler will not receive data, but the credits will not be affected even if we continu to send data with “adl_fcmSendData()”.

Could you explain me how a credit can be loosed ?