Meck/SMS & Phone App Guide.md

SMS & Phone App (Pro 4G & Max) - Meck v1.12.6

Press T from the home screen to open the SMS & Phone app.

Available on the T-Deck Pro 4G and the T-Deck Pro Max. Requires a nano SIM card in the A7682E modem slot and an SD card formatted as FAT32. The modem registers on the cellular network automatically at boot -- the red LED on the board indicates the modem is powered. The modem (and its red LED) can be switched off and on from the settings screen. After each modem startup the system clock syncs from the cellular network, which takes roughly 15 seconds.

Note for US users: the A7682E supports very limited US cellular bands, so 4G is almost entirely unusable with US SIMs. It is wholly unusable on T-Mobile and may have very limited use on AT&T.

App Menu

The app opens to a landing screen with four entries:

Row	Description
Dial	Keypad for calling any number
Call Log	Incoming, outgoing and missed calls, stored on the SD card
Contacts	Saved contacts -- add, edit, dial, message and delete
SMS Inbox	Message conversations

Use W / S to move between rows and Enter to open one. Press Q to return to the home screen.

Two rows carry a count in brackets:

• Call Log [n] -- missed calls you have not yet viewed. Clears when you open the Call Log.
• SMS Inbox [n] -- unread received messages. Clears per conversation as you read them.

Both counts are held on the SD card rather than in memory, so they survive a reboot and only clear when you actually open the relevant screen.

Key Mapping

Context	Key	Action
Home screen	T	Open SMS & Phone app
App menu	W / S	Move between the four rows
App menu	Enter	Open selected row
App menu	Q	Back to home screen
Call Log	W / S	Scroll entries
Call Log	Enter	Dial the highlighted entry back
Call Log	D	Delete the highlighted entry
Call Log	Q	Back to app menu
Contacts	W / S	Scroll contact list
Contacts	Enter	Open the contact page
Contacts	A	Add a new contact
Contacts	M	Compose an SMS to the selected contact
Contacts	F	Call the selected contact
Contacts	Q	Back to app menu (or to the inbox if opened from there)
Contact page	W / S	Move between Name, Number and Save
Contact page	Enter	Edit the highlighted field, or save from the Save row
Contact page	F	Dial this contact
Contact page	D	Delete this contact
Contact page	Q	Back without saving
Field editing	Enter	Commit the field
Field editing	Backspace	Delete last character
Field editing	Shift+Del	Abandon this field edit
Inbox	W / S	Scroll conversations
Inbox	Enter	Open conversation
Inbox	C	Compose new SMS (enter phone number)
Inbox	D	Open contacts list
Inbox	Q	Back to app menu
Conversation	W / S	Scroll messages
Conversation	C	Reply to this conversation
Conversation	F	Call this number
Conversation	A	Add or edit contact name for this number
Conversation	Q	Back to inbox
Compose	Enter	Send SMS (from body) / Confirm phone number (from phone input)
Compose	Shift+Del	Cancel and return
Phone Dialer	0-9, *, +, #	Enter phone number (see input methods below)
Phone Dialer	Enter	Place call
Phone Dialer	Backspace	Delete last digit
Phone Dialer	Shift+Del	Back to app menu
Dialing	Enter or Shift+Del	Cancel / hang up
Incoming Call	Enter	Answer call
Incoming Call	Shift+Del	Reject call
In Call	Enter or Shift+Del	Hang up
In Call	W / S	Volume up / down (0-5)
In Call	0-9, *, #	Send DTMF tone

Exit key: across the T-Deck Pro and Max interface, Q is the back key. The exception is anywhere you are typing -- while text or number entry is active, Q is a normal character, so Shift+Del exits instead. That is why the dialer and the call screens use Shift+Del rather than Q.

Call Log

The Call Log records every call the device handles, stored on the SD card at /sms/calllog.dat so it survives reboots. The 32 most recent calls are kept; older entries are trimmed automatically as new ones arrive.

Each entry shows the contact name where the number is saved (the raw number otherwise), the call type, the duration for calls that connected, and the local date and time.

Type	Meaning
Missed	Rang but was not answered
In	Incoming call that connected, with duration
Out	Outgoing call that connected, with duration

Outgoing attempts that never connect -- busy, or no answer -- are logged as Out with no duration. Calls that arrive with no caller ID are still logged, listed as Unknown; Enter does nothing on those entries as there is no number to dial back.

Press Enter on an entry to call that number back, or D to delete the entry. Opening the Call Log clears the missed-call badge on the app menu and on the lock screen.

Contacts

Contacts assign display names to phone numbers. Names appear in the inbox list, conversation headers, call screens, the call log and the compose screen instead of raw numbers.

Open Contacts from the app menu to see the saved list. From there:

• A adds a new contact.
• Enter opens the highlighted contact.
• M composes an SMS to them.
• F calls them directly.

The contact page is used for both adding and editing. It has three rows -- Name, Number and Save. Move between them with W / S. Press Enter on Name or Number to type into that field: Backspace deletes, Enter commits the field, and Shift+Del abandons that edit. Press Enter on Save to write the contact to the SD card.

A contact cannot be saved without a number, since the number is what the entry is stored against -- attempting to do so leaves you on the page with a "A number is required" prompt. Changing the number of an existing contact replaces the old entry rather than creating a second one.

Press F on a saved contact to dial it, or D to delete it. Q leaves the page without saving, so commit your changes on the Save row first.

Contacts can also still be created from a conversation: press A while reading messages from a number to name it.

Contacts are stored as a plain text file at /sms/contacts.txt in phone=Display Name format -- one per line, human-editable. Up to 30 contacts are supported, and names can be up to 23 characters.

Sending an SMS

There are four ways to start a new message:

1. From the inbox -- press C, type the destination number, press Enter, then type your message and press Enter to send.
2. From a conversation -- press C to reply. The recipient is pre-filled, so you go straight to the message body.
3. From the contacts list -- press M on a contact. The compose screen opens with the number pre-filled.
4. From the inbox contacts view -- press D from the inbox to reach the same contacts list.

Messages are limited to 160 characters. A character counter is shown in the footer while composing.

Making a Phone Call

There are four ways to start a call:

1. From the dialer -- select Dial from the app menu, enter a number and press Enter.
2. From the Call Log -- press Enter on any entry to call it back.
3. From a conversation -- press F to call the number you are reading.
4. From contacts -- press F on the list, or F on the contact page.

The display switches to a dialing screen showing the contact name (or number) and an animated progress indicator. Once the remote party answers, the screen transitions to the in-call view with a live call timer.

During a call, W and S adjust the speaker volume (0-5). The number keys 0-9, *, and # send DTMF tones for navigating phone menus and voicemail. Press Enter or Shift+Del to hang up.

Audio is routed through the A7682E modem's internal codec to the board speaker and microphone -- no headphones or external audio hardware are required.

Phone Dialer Input Methods

The dialer supports three ways to enter digits:

1. Direct key press -- press the keyboard letter that corresponds to each number using the silk-screened labels on the keys:

   Key	Digit		Key	Digit		Key	Digit
   W	1		S	4		Z	7
   E	2		D	5		X	8
   R	3		F	6		C	9
   A	*		O	+		Mic	0

2. Touchscreen tap -- tap the on-screen buttons directly. The bottom row of the keypad carries +, Backspace and Call, so a number can be dialled entirely by touch. Note that this currently requires fairly precise taps on the buttons themselves.

3. Sym+key -- the standard symbol entry method (e.g. Sym+W for 1).

Receiving a Phone Call

When an incoming call arrives, the app switches to the incoming call screen regardless of which view is active. A short alert and buzzer notification are triggered. The caller's name is shown if saved in contacts, otherwise the raw number is displayed.

If the device is locked when a call arrives, it unlocks itself so the call can be answered, and stays unlocked afterwards.

Press Enter to answer or Shift+Del to reject. If the call is not answered it is recorded in the Call Log as a missed call, a "Missed: ..." alert is shown briefly, and the missed-call count appears on the app menu and lock screen.

Lock Screen Notifications

On Pro 4G and Max builds, the lock screen shows any outstanding unread SMS and missed calls below the battery and mesh unread line, for example SMS: 2 Missed: 1. Either part is hidden when its count is zero.

These are read from the inbox and the call log rather than tallied while the screen is locked, so they persist across locking, unlocking and rebooting. They clear only when you open the relevant conversation or the Call Log.

Conversation History

Messages are saved to the SD card automatically and persist across reboots. Each phone number gets its own file under /sms/. The inbox shows the most recent 20 conversations sorted by last activity. Within a conversation the most recent 30 messages are loaded, newest at the bottom. Sent messages are shown with >>> and received messages with <<<.

Message timestamps use the cellular network clock (synced via NITZ roughly 15 seconds after each modem startup) and display as relative times (e.g. 5m, 2h, 1d). If the modem is toggled off and back on, the clock re-syncs automatically.

Modem Power Control

The 4G modem can be toggled on or off from the settings screen. Scroll to 4G Modem: ON/OFF and press Enter to toggle. Switching the modem off kills its red status LED and stops all cellular activity. The setting persists to SD and is respected on subsequent boots -- if disabled, the modem and LED stay off until re-enabled. The SMS & Phone app remains accessible when the modem is off, but cannot send or receive messages or calls.

Signal Indicator

A signal strength indicator is shown in the top-right corner of all SMS and call screens. Bars are derived from the modem's CSQ (signal quality) reading, updated every 30 seconds. The modem state (REG, READY, OFF, etc.) is shown when not yet connected. During a call the indicator remains visible.

IMEI, Carrier & APN

The modem's IMEI, current carrier name, and APN are displayed at the bottom of the settings screen (press S from the home screen), alongside your node ID and firmware version.

SD Card Structure

SD Card
├── sms/
│   ├── contacts.txt           (plain text, phone=Name format)
│   ├── calllog.dat            (binary, 32 most recent calls)
│   ├── modem.cfg              (0 or 1, modem enable state)
│   ├── 0412345678.sms         (binary message log per phone number)
│   └── 0498765432.sms
├── books/                     (text reader)
├── audiobooks/                (audio variant only)
└── ...

Troubleshooting

Symptom	Likely Cause
Modem icon stays at REG / never reaches READY	SIM not inserted, no signal, or SIM requires PIN unlock (not currently supported)
Timestamps show ---	Modem clock hasn't synced yet (wait ~15 seconds after modem startup), or messages were saved before clock sync was available
Red LED stays on after disabling modem	Toggle the setting off, then reboot -- the boot sequence ensures power is cut when disabled
SMS sends but no delivery	Check signal strength; below 5 bars is marginal. Move to better coverage
Call drops immediately after dialing	Check signal strength and ensure the SIM plan supports voice calls
No audio during call	The A7682E routes audio through its own codec; ensure the board speaker is not obstructed. Try adjusting volume with W/S
Contact will not save	The Number field is empty -- a contact is stored against its number, so one is required
Call Log entry shows "Unknown"	The network withheld the caller ID, or it did not arrive before the caller rang off. The call is still logged
Missed-call count will not clear	It clears when the Call Log is opened, not when the device is unlocked

Note: The SMS & Phone app is available on the 4G variants of the T-Deck Pro and on the T-Deck Pro Max. It is not present on the audio or standalone BLE builds of the T-Deck Pro, due to shared GPIO pin conflicts between the A7682E modem and the PCM5102A DAC. The Max avoids that conflict by wiring its modem and ES8311 codec through an XL9555 I/O expander, so it has both.