Phone

contents

faxzero.com, usa free, international $2, the only payment method is paypal
hellofax.com, by Dropbox, I created a free account, good for 5 faxes, looks like it will take a credit card

• Receiving calls and texts from anywhere in the world is free no matter where you are.
• Calling and texting to US and Canadian numbers is free no matter where you are.
• Calling other numbers subject to published by Google rates, you need to buy credit beforehand.
• Texting other numbers is not available with GV.

\Phone Numbers

Mobile Phones

Uses of a mobile phone:

• Phone calls - point-to-point connection between two phone numbers.
• Texting - point-to-point sending of messages which might include text, image, video.
  • SMS - Short Message Service
  • MMS - Multimedia Message Service
  • Text messaging - a casual, everyday language term referring to SMS and/or MMS
• Data - an IP-based connection to the internet over a cellular network.
  • VoIP - once you have data, from either WiFi or SIM, then you can do simulated phone calls,and video conferencing
  • hybrid VoIP-to-Cellular - Some VoIP apps may connect VoIP to cell phones
  • VoIP apps include: Google Voice, OneSimCard, Skype, Line, Zoom, WhatsApp, Skype, Google Meet, and more.

Texting and phone calls use one network. Data uses another. Both networks are managed by cellular carriers.

Phone calls and SMS

SIM Card
Subscriber Identity Module (SIM)

1991 - First SIM cards, the size of a credit card
1996 - mini SIM cards
2003 - micro SIM cards
2012 - nano SIM cards
2016 - Embedded SIM, eSIM, built in to the phone by the manufacturer, programmable

Since the emergence of the eSIM, the older SIMs are called “physical” or “plastic” SIMs.

The SIM contains:

• International Mobile Subscriber Identity (IMSI) - a 64-bit number inside the chip
• SIM profile - phone number, network, carrier.
• Integrated Circuit Card Identifier (ICCID)

Also, the phone contains:

• International Mobile Equipment Identity (IMEI) - 15 digit number identifies the SIM slot

A dual SIM phone has two slots, and therefore two IMEI numbers.
The newest high-end phones are often dual-SIM phones with one plastic and one eSIM.

eSIM
embedded SIM (eSIM)
An eSIM can hold multiple SIM profiles but usually only one is active at a time.
Dual SIM Dual Standby (DSDS) - This is a feature that allows for two SIM profiles to be actively listening for calls simultaneously. This applies either to one eSIM and one SIM, or to two eSIMS.
Dual SIM Dual Active (DSDA) - This is very rare because it requires a second radio in the phone. It would allow talking to two conversations simultaneously, or talking on one line while using data on the other line.

T-Mobile

• Activate in the USA. Roam internationally. Always have access to a US phone number.
• Fine print: “Not for extended international use; you must reside in the U.S. and primary usage must occur on our U.S. network. Device must register on our U.S. network before international use.”

US Phone Number
Some US banks require their customers to have a US address and a US phone number. This number will be used to receive text messages, like for the OTP for 2FA.

I normally use the 847-xxx-xxxx number at Google Voice.
And I make calls using Skype with the outgoing number set to 847-xxx-xxxx.

When I called Chase bank for a second OTP, he said that because I gave the account number and called on my registered phone number, that was the first step to authentication.

He asked me what number he should use to send the OTP. Presumably I could have given him a cell phone number, but I’m guessing he would expect a US number.

A OneSimCard comes with a US Number, but evidently it is not a real US number, because some banks refuse to use it for 2FA.

SIM Card 2FA
Has security flaws.

Some banks and brokerages require a US address and a US phone number.
The address can be provided by a friend or family.
The phone number can be provided by:

• Google Voice - answering service only. OK to receive texts and messages but cannot call out.
• Skype - discontinued in May 2025
• T-Mobile SIM card - using international roaming. Not allowed for extended international use.
• A dedicated landline in the friends house forwarded to a cell phone.

AIS Roaming
https://olmd.ais.th/roaming/en/howto.html

Receives calls, records voicemails, and forwards transcription to me via email.
Receives texts and forwards them to me via email.
Useful for receiving 2FA OTP codes.

Outgoing calls.
Caller ID is my 847 number.
For US numbers it’s free.
For foreign numbers there is a per minute charge depending on the country, shown here:
https://voice.google.com/u/0/rates

Call forwarding to “linked” numbers.
Create a “linked number” in Settings→Account.
US numbers only, landline or mobile. How about the OneSimCard VoIP number?

During install:
Link this device to Google Voice.
Make and receive Google Voice calls with this device.
Don’t want to make Google Voice calls with this device? Verify your account with a different phone number. (Skip)
Allow Voice to access your contacts?
Turn on notifications.
Let Google Voice use your Bluetooth devices with WiFi calls and voicemail.

When trying to make a call:
Before making a call, please verify your own number.
When I proceeded it tried to add my Thai SIM number to my Google Voice account as a “linked” number.
I want to use WiFi, same as I do on my laptop.
However, it is interesting to note that it seems to be able to forward to a foreign number.

Why does Google voice Android need permission to manage phone calls if I’m using VoIP?

Use old phone to test Google voice.

Belmont MA
The product I have is DATAMAX SIM plastic.

Several data packages are available, named

• Zone Basic
• Zone Extended
• Zone Giga
• Zone Euro

Here is a list of the countries supported by each Zone: https://docs.google.com/spreadsheets/d/1LtJ7sIQe7jhFJsOZ59ObiCt8yt7rYGmsnoAxZ-ECFrs/edit?usp=sharing

Here is a list of the packages offered by zone, days, and MBs:

The Zone Extended package has all of the countries I need.

The number provided is a US phone number, but it is VoIP-based, which means it is detected and cannot be used for 2FA.

Google Voice
US-focus
voice and SMS
OneSimCard DataMAX
global-focus
data