[Off-topic] lm22222:
so, why i choose xmpp and sip ?

instead of going on whatsapp, telegram, signal..

firstly, what are those two protocols?

SIP is a protocol to do phone communications over the internet. Eg, Linphone is both a client/application/software (computer, phone), but also a SIP service provider.

Both can be dissociate : you can use linphone service with a hardware sip phone. You can use linphone software or app with different/multiple providers (even not linphone)

xmpp is a protocol to communicate through internet : secured messages, plus voice/video. Like SIP. Conversations and quicksy are the most recommended xmpp client/application for android. You can find Monal on iPhone, Gajim and Dino for windows, macos, linux, unix.

to compare, if you didnt understood :

imap and smtp are making emails services works. without imap/smtp, you just can't use emails. (i exclude mapi/exchange to not complicate things)

alice@first.net is an email. it can be also also be a SIP address, or xmpp one.

it's called an URI.

bob@conversations.im is not an email. it's bob's xmpp address (or URI)

then, why xmpp or sip, where others exists too?

* 1- SIP manages very well voice and video calls. xmpp manages very well the same services.

two protocols, but... why?? => if one of them is just out of order, unavailable, the second one can carry one. that's why. Never only one.

* 2- both are federated or interoperable, like email : alice@first.net could reach bob@second.org (you call signal/telegram users with whapp? No, you cant)

* 3- that means there is a failure tolerance, in case of unavailability : when whatsapp is unavailable (yes, it happened, not only once), no one can communicate. With SIP, if callcentric is out of order for a while, voip.ms can't call those of others providers, like emails : if gmail is down, yahoo can still reach protonmail's users. Exactly like if ATT is unavailable : sprint/verizon can still reach tmobile. It's a requirement.

* 4- they can be used on a computer (not damn javascripted web!) with a software client, for sip (eg linphone, others exists), or xmpp : Dino, Gajim..

* 5- they are secured : omemo for xmpp, srtp/zrtp for SIP.

* 6- those two technos are free and standardised, means compatible with others, instead of the "three bigs" demanding to get the same app for communications

* 7- servers for xmpp are mainly from voluntary, non profit organisations, whom respects privacy and RGPD more than big four. You're not the product.

* 8- Quicksy is the alter-ego of whatpp in a practical way, just because it uses only the phone number. Only thing it shares with whapp.

* 9- it permits to distinguish the software/application/client, from the service (i hate simplified things : always divide to reign better !)

* 10- you might hear that whatsapp, and others gafam's tools (teams, hangouts) were using both xmpp and sip at early hours : it's true, but why not use directly xmpp/sip client + service instead of their whole marketing package software? same for skype or teams, who had used (and uses) SIP

* 11- there is a real community with it, whom accompany and develops the software and protocol

* 12- skype is from, about/approx, 2005. iMess around 2011? whatsapp near the same. SIP and XMPP? in 2000, they where already here. It's not the firsts here to have to adapt ;)

* 13- opensource world is a bit tired of the Embrace, extend, and extinguish, first weapon of gafam in communications :

Embrace, extend, and extinguish - Wikipedia

en.wikipedia.org

hey, that's a gift :

Debian Pastezone

paste.debian.net

TBH, on my own : i just dont understand how to be "okay" with using those big messaging tools. I dont.

if relatives are not happy, a text message (sms) or an email, still works. Yep, technology-type prevails on the contact. Yep. Some people are proud to be "grammar-nasi", for me it's the technology, and i wont change for your eyes :)

i tried to do my best writing this, if you want to correct errors..

hello,

No, as always replied : i wont have whatsapp, nor yesterday, not today, not more tomorrow.

only alternative to whtasapp me : to transmit me the device, with the sim card inserted and the application installed, through post mail, ready to use, obviously at fees or charges of the person whom wants to reach me on it, with a dedicated phone, of course. I wont spend a penny for it, never.

my private phone number wont be, even for "a million eur/usd", reachable on whatpp. Decision will change for nobody.