Caller ID: the CallingLineIdentity machine
CsCallingLineIdentity policies decide the outbound presentation per user class:
- Identity substitution: show the user's DID (default), a SERVICE number (the main-office pattern — everyone presents +44 20 7946 0000), or Anonymous.
- Inbound blocking:
BlockIncomingPstnCallerIDstrips PSTN CLI display. - User override: policy can allow users to toggle anonymity per call.
Sharp edges: substituting a service number requires that number to be a real, assigned service number (Microsoft validates); regulatory reality is that some countries constrain CLI manipulation — presenting numbers you don't hold is a carrier-contract violation before it's a Teams question. On Direct Routing, the SBC/carrier can rewrite CLI again downstream — when 'wrong number showing' tickets arrive, establish WHERE the number changed (policy vs SBC header manipulation) before touching anything.
Voicemail: the answering machine in Exchange
Unanswered-call handling follows the user's calling settings (un-answered ring
duration then voicemail/forward/nothing) inside TeamsCallingPolicy allowances.
Messages: recorded by the voicemail service, stored in the user's Exchange
mailbox, transcribed (per OnlineVoicemailPolicy — transcription on/off,
profanity masking, translation; 4 instances in a typical tenant, all scanned).
Consequences of the mailbox home: no EXO mailbox = no voicemail; retention/holds
apply like any mail; leavers' voicemails follow mailbox offboarding.
Shared voicemail (AA/CQ overflow target) lands in a GROUP mailbox — governance as per the call-queues concept.
What to watch (proofs)
- Presentation truth per user:
Get-CsCallingLineIdentity | fl+ the user's assignment — then one test call to a mobile; the display IS the test. - CLI rewrite hunting (DR): SBC egress SIP trace — From/PAI headers on the wire vs what policy set; the diff locates the rewrite.
- Voicemail policy census:
Get-CsOnlineVoicemailPolicyall instances (nightly in serv365 — EnableTranscription et al. already appear in your tenant search). - Delivery proof: leave a test voicemail → arrives as mail item with transcription in the mailbox (visible via Outlook/eDiscovery) — storage claim, demonstrated.