SMS & Calls
Receive verification codes without a phone
Page 34 reuses the serial port and AT channel of the 4G module from page 32 and does two things: SMS (list, send, delete, check SIM storage) and calls (incoming state, answer, hang up).
Chinese SMS must be sent as UCS2, and the **number has to be converted too** β converting only the body makes the module answer ERROR. While sending, the module emits a `> ` prompt without a newline; the body can only be pushed after it appears, otherwise the message never leaves.
The AT channel is exclusive: GNSS polling fires and forgets, SMS sends and waits, so interleaving them merges the OK responses and looks like "sending always times out". This page pauses GNSS polling while sending and resumes afterwards.
On-screen interface
A recreation of this page on the 2.41-inch AMOLED display (600 Γ 450). Actual interaction and layout follow the latest firmware.
Key capabilities
Send and receive
List, read, send, delete β SIM storage included.
UCS2 Chinese
Number and body converted together, no garbled text.
Call handling
See an incoming call, answer or hang up without a phone.
Exclusive channel
GNSS polling yields during a send so replies never interleave.
Technical specs
Typical scenarios
Verification codes
The device receives the code itself when no phone is around.
Fallback channel
If WiFi is down, an SMS can still carry a command in.
Related commands
page 34 Open the SMS page sms Module state and unread count sms ls List messages by storage index sms send <number> <text> Send an SMS, Chinese converted to UCS2 automatically sms read 3 / sms del 2 Read or delete message 3 / 2 call <number> | answer | hangup Dial, answer or hang up
- Needs a 4G module with a registered SIM and usable signal.
- Shares the serial port with page 32 β only one of them can own the AT channel at a time.
- Chinese counts as UCS2: 70 characters per message, longer text is split.