How Calling and Texting Work

What's actually there

The top navigation bar's phone icon (tooltip: "Call or Text") opens two separate tools:

• Call — opens the softphone, a full in-browser phone: dial pad, live calls, call history, voicemail, department speed dial, and call settings (forwarding, Do Not Disturb, auto answer). Backed by a real calling stack — RingCentral's WebPhone SDK, SIP.js (for a standards-based PBX like FreePBX/Asterisk), or Azure Communication Services (Microsoft Teams), depending on which phone provider your organization connected.
• Text — opens the SMS/bulk-text tool: start and hold text conversations, with built-in canned reply templates.

Both are gated on your organization having phone turned on and you holding the Access VOIP right.

"tCall"

We went looking for a distinct feature or product named "tCall" and didn't find one anywhere in the codebase — not as a component name, a translation key, a service name, or a mention in any related repo (voipservice, kamo-asterisk-support). There's no evidence it's a real, separate thing. It most likely refers informally to this same Call/softphone feature described above, or was a misremembered name — there's nothing else in the product it could plausibly point to.