The Command resource enables you to exchange simple machine-to-machine messages with SMS-capable devices. For example, you could use a Command resource to instruct a device to take a sensor reading.
While SMS is used as the transport, the SIM does not require an addressable phone number to receive a Command. This is the major distinction from Twilio's Messages resource, which can be used for conversational messaging.
Any SMS message sent from a SIM to a pre-determined phone number — see Receive a Command from a SIM — is interpreted as a Command and sent to the Command callback URL of the Sim resource.
Commands can be sent and received using the SMS text mode or binary (PDU) mode. Text-mode Commands have a maximum length of 160 single-byte characters. Binary-mode Commands have a maximum length of 140 bytes.
To receive and process a Command sent to your device, you will interface with the modem directly, probably using AT commands. You should consult with the module manufacturer's documentation for information about receiving SMS messages.
The Command resource performs asynchronous operations. To receive an asynchronous notification when a Command resource has finished updating, provide a callback URL, and optionally a callback method, GET or POST, when you create the Command.
Commands are retained for 30 days from the time they are created. Commands older than 30 days will no longer be readable from this resource.
The unique string that we created to identify the Command resource.
^DC[0-9a-fA-F]{32}$Min length: 34Max length: 34The SID of the Account that created the Command resource.
^AC[0-9a-fA-F]{32}$Min length: 34Max length: 34The SID of the Sim resource that the Command was sent to or from.
^DE[0-9a-fA-F]{32}$Min length: 34Max length: 34The message being sent to or from the SIM. For text mode messages, this can be up to 160 characters. For binary mode messages, this is a series of up to 140 bytes of data encoded using base64.
The mode used to send the SMS message. Can be: text or binary. The default SMS mode is text.
textbinaryThe status of the Command. Can be: queued, sent, delivered, received, or failed. See Status Values for a description of each state.
queuedsentdeliveredreceivedfailedThe direction of the Command. Can be to_sim or from_sim. The value of to_sim is synonymous with the term mobile terminated, and from_sim is synonymous with the term mobile originated.
from_simto_simThe date and time in GMT when the resource was created specified in ISO 8601 format.
The date and time in GMT when the resource was last updated specified in ISO 8601 format.
The absolute URL of the resource.
| Status | Description |
|---|---|
queued | The Command is queued in our network waiting to be sent to the SIM. |
sent | The Command has been sent to the SIM. |
delivered | The Command has been delivered to the SIM. For to_sim Commands only. |
received | The Command has been received from the SIM. For from_sim Commands only. |
failed | The Command has failed to be transmitted. |
POST https://wireless.twilio.com/v1/CommandsCreating a Command resource sends the command to the SIM.
Outgoing Command delivery is asynchronous, so we recommend that you pass a callback URL when you create the new Command.
When you provide a callback URL, we call it when the attempt to send the Command completes.
We send these parameters to the callback URL:
| Parameter | Description |
|---|---|
CommandSid | The Command this callback is in reference to. |
CommandStatus | The current status of the Command. |
SimSid | The SIM this Command was sent to. |
SimUniqueName | The receiving SIM's UniqueName, if it has one. |
ErrorCode | If an error occurred, an error code is provided. |
ErrorMessage | If an error occurred, an error message is provided. |
ApiVersion | The version of the API that your initial request was made to. |
AccountSid | The SID of the Account that this Command belongs to. |
CommandMode | A string representing which mode the SMS was sent using. May be text or binary. |
If the CallbackMethod parameter was set to POST, or not provided, the callback parameters are delivered as HTML form parameters. If the CallbackMethod parameter was set to GET, the callback parameters are delivered as a query string.
The message body of the Command. Can be plain text in text mode or a Base64 encoded byte string in binary mode.
The HTTP method we use to call callback_url. Can be: POST or GET, and the default is POST.
GETPOSTThe URL we call using the callback_url when the Command has finished sending, whether the command was delivered or it failed.
The mode to use when sending the SMS message. Can be: text or binary. The default SMS mode is text.
textbinaryWhether to include the SID of the command in the message body. Can be: none, start, or end, and the default behavior is none. When sending a Command to a SIM in text mode, we can automatically include the SID of the Command in the message body, which could be used to ensure that the device does not process the same Command more than once. A value of start will prepend the message with the Command SID, and end will append it to the end, separating the Command SID from the message body with a space. The length of the Command SID is included in the 160 character limit so the SMS body must be 128 characters or less before the Command SID is included.
Whether to request delivery receipt from the recipient. For Commands that request delivery receipt, the Command state transitions to 'delivered' once the server has received a delivery receipt from the device. The default value is true.
Send the ‘wakeup' command to the ‘AliceSmithSmartMeter' SIM
Send a binary command to the ‘AliceSmithSmartMeter' SIM
GET https://wireless.twilio.com/v1/Commands/{Sid}The SID of the Command resource to fetch.
^DC[0-9a-fA-F]{32}$Min length: 34Max length: 34GET https://wireless.twilio.com/v1/CommandsThe maximum PageSize you can request when reading Commands is 100.
The status of the resources to read. Can be: queued, sent, delivered, received, or failed.
queuedsentdeliveredreceivedfailedOnly return Commands with this direction value.
from_simto_simOnly return Commands with this transport value. Can be: sms or ip.
smsipHow many resources to return in each list page. The default is 50, and the maximum is 1000.
1Maximum: 1000The page token. This is provided by the API.
DELETE https://wireless.twilio.com/v1/Commands/{Sid}The SID of the Command resource to delete.
^DC[0-9a-fA-F]{32}$Min length: 34Max length: 34To receive a Command from a SIM — called a "mobile-originated" Command — you should create or update an existing Sim instance and provide a CommandsCallbackUrl property. Optionally, you may also include a CommandsCallbackMethod property.
When a SIM sends an SMS message to the reserved phone number 2936, a Command resource will be created, and your Commands Callback URL will be invoked. The callback request will include the following parameters.
| Parameter | Description |
|---|---|
CommandSid | The SID of this Command. |
SimSid | The SIM this Command was sent by. |
SimUniqueName | The sending SIM's friendly name, if it has one. |
Command | The body of the Command message. In text mode, this value can be up to 160 characters of text. In binary mode, this value is a Base64 encoded byte string with a maximum size of 140 bytes. |
Status | Will always be the string received. |
ApiVersion | The version of the API that your initial request was made to. |
AccountSid | The SID of the Account that this Command belongs to. |
CommandMode | A string representing which mode the SMS was received as. May be text or binary. |