SMS Messaging FAQ.

All of the models, GSM/GPRS, CDMA, and EDGE, use almost identical commands for SMS.

QUESTIONS:

Q: What is the maximum amount of characters I can use to send an SMS message?
Q: How do I send an SMS message manually using Hyperterminal?
Q: How do I read messages that are received?
Q: How do I delete a stored message?
Q: How do I change the SMS storage locations?
Q: If the SMS storage location becomes full, what will happen?
Q: On the GSM/GPRS models, after I change the +CNMI, +CSCA, or +CSMP commands, it doesn’t store?
Q: How do I send an SMS message to email accounts? (GSM/GPRS models only)
Q: Do you have an example of how to send an SMS message to an email account?
Q: How do I route the received SMS messages directly to the terminal equipment (TE)?
Q: Is there a way to set the modem to assign a priority to an SMS message?





ANSWERS:

Q: What is the max amount of characters I can use to send a SMS message?

- Supports up to 160 characters max.
- In PDU mode using 7-bit the modem still supports 160 characters, but in 8-bit mode the modem will only support 70 characters.
- CDMA does not support PDU mode.


Q: How do I send an SMS message manually using Hyperterminal?

- AT+CMGF=1 (command not valid in CDMA models)
- AT+CMGS="<phone#>"
-<type message here><ctrl + Z>


Q: How do I read messages that are received?

- AT+CMGR=n (where n equals the stored location of the message)
- AT+CMGL (this command lists the messages by status, look in reference guide for list of values)


Q: How do I delete a stored message?

- AT+CMGD=n (where n equals the stored location of the message)
- AT+CMGD=1,4 (On CDMA and GSM/GPRS models: will delete all the stored messages in the currently selected storage location, look in the reference guide for more list of values)


Q: How do I change the SMS storage locations?

- The +CPMS command controls the SMS storage locations.


Q: If the SMS storage location becomes full, what will happen?

- Modem will not receive anymore messages from the server until there is space available. Delete some messages once the storage location becomes full.


Q: On the GSM/GPRS models, after I change the +CNMI, +CSCA, or +CSMP commands, it doesn’t store?

- When changing these commands, you must use the +CSAS command to store the changes.


Q: How do I send an SMS message to email accounts? (GSM/GPRS models only)

- When sending an SMS message to an email account you must use a designated routing number that will tell the SMS server to route your message to an email account. Here are the some numbers:
AT&T = "0000"
T-Mobile = "500"
Cingular = "121"


Q: Do you have an example of how to send an SMS message to an email account?

- AT+CMGS="0000"
->email@multitech.com My message goes here.<ctrl + Z>


Q: How do I route the received SMS messages directly to the terminal equipment (TE)?

- The +CNMI setting controls how the messages are routed and stored. Setting the "MT" settings for this command to 2 will cause the SMS messages to be routed directly to the TE. Example: AT+CNMI=0,2,0,0,0
- When messages are routed directly to the TE on the CDMA models, an acknowledgement will need to be sent after a message is received from the network.‘AT+CNMA’ will send an acknowledge to the network. If an acknowledgement is not sent within the providers specific time-window, the provider will keep the message on the server and keep sending the same message over-and-over again until the acknowledgement is received.
- When messages are routed directly to the TE on the GSM/GPRS models, an acknowledgement (AT+CNMA) is not required unless you set‘AT+CSMS=1’. If an acknowledgement is not sent within the providers specific time-window, the provider will keep the message on the server and keep sending the same message over-and-over again until the acknowledgement is received.
- This feature is not supported on the EDGE models.


Q: Is there a way to set the modem to assign a priority to an SMS message?

- No, you cannot do that.