I've been working on a website where there will be two buttons: "Call us" and an "SMS us". The user might be on mobile or on a desktop browser, and I'd like to make it clear that the SMS icon means "send an SMS" not "whatsapp us".
There will be text on the buttons but I'm looking for an icon that better represents "send us an sms" specifically, not chatting. Most of the icons I've found are either a variation of the chat bubble (square, round) or it says "SMS" inside the bubble, like these examples https://fontawesome.com/icons?d=gallery&q=sms&m=free
When I do a google search I get many other variations, some with the balloon inside / on top of a mobile icon, some with 2 balloons implying a chat, some with an envelope (which can be confused with "email") but I'm wondering: is there one that is the "standard" for SMS icon?