Command Resource
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.
Asynchronous resources
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.
Retention period
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.
Command properties
| Resource Properties in REST API format | |
|---|---|
sid
|
The unique string that we created to identify the Command resource. |
account_sid
|
The SID of the Account that created the Command resource. |
sim_sid
|
The SID of the Sim resource that the Command was sent to or from. |
command
|
The 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. |
command_mode
|
The mode used to send the SMS message. Can be: |
transport
|
The type of transport used. Can be: |
delivery_receipt_requested
|
Whether to request a delivery receipt. |
status
|
The status of the Command. Can be: |
direction
|
The direction of the Command. Can be |
date_created
|
The date and time in GMT when the resource was created specified in ISO 8601 format. |
date_updated
|
The date and time in GMT when the resource was last updated specified in ISO 8601 format. |
url
|
The absolute URL of the resource. |
Status values
| 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. |
Create a Command resource
https://wireless.twilio.com/v1/Commands
Creating a Command resource sends the command to the SIM.
Callback values
Outgoing Command delivery is asynchronous, so we recommend that you pass a callback URL when you create the new Command.
When you providea 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.
Parameters
| Parameters in REST API format | |
|---|---|
command
Required
|
The message body of the Command. Can be plain text in text mode or a Base64 encoded byte string in binary mode. |
sim
Optional
|
The |
callback_method
Optional
|
The HTTP method we use to call |
callback_url
Optional
|
The URL we call using the |
command_mode
Optional
|
The mode to use when sending the SMS message. Can be: |
include_sid
Optional
|
Whether to include the SID of the command in the message body. Can be: |
delivery_receipt_requested
Optional
|
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 |
Example 1
Example 2
Fetch a Command resource
https://wireless.twilio.com/v1/Commands/{Sid}
Parameters
| Parameters in REST API format | |
|---|---|
sid
Path
|
The SID of the Command resource to fetch. |
Example 1
Read multiple Command resources
https://wireless.twilio.com/v1/Commands
The maximum PageSize you can request when reading Commands is 100.
Parameters
| Parameters in REST API format | |
|---|---|
sim
Optional
|
The |
status
Optional
|
The status of the resources to read. Can be: |
direction
Optional
|
Only return Commands with this direction value. |
transport
Optional
|
Only return Commands with this transport value. Can be: |
Example 1
Delete a Command resource
https://wireless.twilio.com/v1/Commands/{Sid}
Parameters
| Parameters in REST API format | |
|---|---|
sid
Path
|
The SID of the Command resource to delete. |
Example 1
Receive a Command from a SIM
To 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. |
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