Local modems

A local modem is a USB 4G modem with a SIM card in it, plugged into a computer (Windows, macOS or Linux) that runs the HelloCall desktop app. The app talks to the modem; the call itself — listening, understanding and speaking — runs on the same HelloCall engine as every other call. The SIM only carries the audio.

• Your own mobile plan pays the carrier. Calls go out on the SIM’s plan, so an unlimited plan means no per-minute carrier bill.
• HelloCall does not charge talk time on a local line. A call on a SIM is not billed per second or per minute; only the AI tokens the call uses come from your wallet.
• Several SIMs on one computer give you several lines. Campaigns spread their calls across free modems.
• A SIM can also send and receive SMS, from the number’s own page.

• A supported modem. HelloCall works with SIMCom SIM7600-series USB modems, which carry call audio over USB. The HelloCall USB modem sold in the console is one — see Device store and devices.
• A SIM card with a voice plan, inserted in the modem, with its PIN lock turned off.
• A computer that stays on while you want the line to work, with a USB port and an internet connection.
• The HelloCall desktop app, signed in to your organisation. See The desktop app.

1. 1 Install the desktop app on the computer the modem will be plugged into, open it and sign in with Google.
2. 2 Insert the SIM into the modem and plug the modem into a USB port.
3. 3 In the app, open Settings → Local modem. The modem appears on its own within a few seconds, with its signal, operator and SIM details.
4. 4 Press Run checks in the modem’s menu and make sure every line is ticked — especially USB call audio.
5. 5 On the modem card, press Not enabled · enable it, give the SIM a name, type its number if it does not report one, and choose its workflows.
6. 6 Place a test call from Test call on the modem card, or with the Call dialog.

Settings → Local modem lists the modems of the desktop app on the computer you are using, one card each. Refresh reads them again. Inside the desktop app this page has two tabs, Modems and Desktop app; in a browser it shows the modems only.

Each modem card shows:

• Chips — Connected or Disconnected, Switched off, No network, the SIM state (Needs PIN, No SIM, Unknown), and whether it is a phone number already (routed or not routed) or Not imported · import it.
• Signal — five bars, a word for the quality and the strength in dBm.
• Network — the operator (or Not registered), the network type, the band and RSRP.
• Now — Idle — free for calls, an incoming, dialling or ringing call, On a call with …, or Switched off. During a call a Live transcript link appears.
• Today — calls placed and SMS sent today.
• SIM card — the phone number, SIM state, ICCID and IMSI.
• Device — model, firmware, IMEI, USB id, AT port and Call audio (“USB audio · 8 kHz”, or “No USB audio”).

Modems plugged into other computers are listed under Local numbers on other computers, with whether each is online.

On Phone numbers, a local number’s provider column shows what its SIM is doing right now:

• Free — ready for calls; the operator is shown beside it.
• Ringing — an incoming call, with the caller’s number.
• Busy · on a call — in a call.
• No network — the SIM is not registered on a network. Check the signal and the SIM’s plan.
• No SIM / SIM locked — insert the SIM, or turn off its PIN lock in a phone.
• Offline — the modem is not connected, it is switched off in its settings, or the desktop app is not running. Hover for the exact reason.

Choose Test call in a modem card’s menu to check the modem end to end. Type the Number to call — usually your own mobile — pick What to test, and press Call now. Answer your phone to hear the test.

• Welcome message (on this computer) — you hear “Welcome to HelloCall app”, then it hangs up.
• Play a melody (on this computer) — a short tune, twice.
• Echo (on this computer) — after each tone, what you said is played back to you. The best test of audio in both directions.
• Say a message (online) — HelloCall speaks the text you type, up to 500 characters.
• Listen & transcribe (online) — HelloCall writes down a sentence you say and reads it back.

Run checks tests everything a console call needs and shows a tick or a cross for each: Modem on USB, AT command channel, SIM card, Network registration, Signal strength, Voice call control, SMS sending, SMS receiving, USB PCM call audio control, DTMF keypad tones and USB call audio. The last line, HelloCall compatibility, says whether calls, USB call audio and SMS all check out.

AT commands in the card’s menu lists every command the modem says it supports, with a search box — try “CSQ” (signal) or “CPCM” (audio). It is a reference for technical support: clicking a command copies it, and nothing is sent to the modem from this list.

Many SIMs do not know their own phone number. Set SIM number writes it onto the SIM card, so it stays with the SIM whichever modem it is in.

1. 1 Open the modem card’s menu and choose Set SIM number.
2. 2 Type the number with its country code in SIM number.
3. 3 Press Save to SIM.

If the SIM refuses the write, the number is saved in the app instead and the message says so; it still works for that modem.

Choose Settings in the card’s menu:

• Label — a name for the modem, for example “Counter SIM”.
• Answer incoming calls automatically — on by default.
• Ring for (seconds) before answering — 0 to 30, 3 by default.
• Default country code — added to numbers typed without one; +91 by default.

Reset modem restarts the modem. It drops any call in progress and is back in about 20 seconds. Hang up appears in the menu while a call is on.

When a local number rings, the desktop app answers it after the ring delay and runs the number’s Incoming workflow, exactly like a Plivo number. For that to happen the app must be signed in, Answer incoming calls automatically must be on, and the number must have an incoming workflow.

A call that could not be answered is still filed in Call history, with a duration of zero and the reason:

• “Missed — no console was open to answer with”
• “Missed — the caller hung up while it was being answered”
• “Missed — nothing answered (no incoming workflow, or auto-answer off)”

A local number’s page has an SMS card: the messages this SIM sent and received, with All / Received / Sent filters and a search box. New SMS composes a message — To and Message, up to 640 characters — and Reply answers one.

• Sending needs the desktop app connected on this computer.
• Long messages go as several parts: 160 characters per part, or 70 in Hindi and other non-Latin scripts.
• The message history is kept in this browser. Received messages appear the moment the SIM gets them while the page is open.

A campaign whose Call from number is a local modem is dialled by the console running on the modem’s computer — the HelloCall server never dials a SIM itself. The Campaigns page shows a section On local numbers for these campaigns.

1. 1 Create the campaign as usual and choose a SIM line in Call from.
2. 2 On the modems’ computer, open Campaigns in the desktop app (or in a browser while the app runs).
3. 3 Press Run here on the campaign card and confirm.
4. 4 Leave the app running. Its window can be closed — the app keeps dialling from the tray.

The card shows contacts, to call, on a call and done, how many calls run at once, and the calls in progress with the modem each is on. Stop stops this computer dialling; calls already out finish on their own. Each contact is claimed before it is dialled, so nobody is called twice even with two tabs open.

• 200 outgoing calls and 200 SMS per SIM per day. The cap protects the SIM from being flagged by the carrier as a telemarketer; it resets at midnight. Add SIMs for more volume.
• One call per SIM at a time. A campaign uses every free modem, up to its own Calls at the same time.
• Transfer to human does not work on a local line — a SIM call cannot be bridged to a second number. Use a Plivo number for flows that hand over to a person.
• Scheduled calls are placed from Plivo numbers only for now.
• Call recordings are a Plivo feature; transcripts are kept for local calls as for any other.