ZTA LabFree University

T9 · T9-R27 · E911 and analytics

Numbers you may repeat, and numbers you may not

A number is allowed in this lab only when you can point at the page. The four numbers above have pages. A fifth number that feels familiar, such as a well-known delay budget, stays confirm because it was not on the text that was read.

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Learn it in 5 minutes

  • Zoom's API sample shows expires_in 3599, and the prose says tokens are valid for one hour.
  • Talkdesk's authentication markdown front matter says updatedAt 2026-09-10.
  • IANA's SIP registry page says Last Updated 2026-08-17.
  • Wikipedia's Avaya extract says more than 90,000 customers.
  • Prices, ports, exam scores, and roadmap months were not opened.

Visual

Numbers you may repeat, and numbers you may not Numbers. Teaching sketch. Confirm a live system. 3599 2026-09-10 90,000 confirm Names come from pages opened in 2026-10. A missing name stays confirm.

Count the boxes: 4. Each label is a name from a page or a study label marked on the drawing.

Flow

Numbers you may repeat, and numbers you may not Caller SIP Called session setup session setup RTP, not required to hairpin Teaching sketch from RFC 3261 and RFC 3550. Not a packet capture.

What is going on

A number is allowed in this lab only when you can point at the page. The four numbers above have pages. A fifth number that feels familiar, such as a well-known delay budget, stays confirm because it was not on the text that was read.

Customer counts are not trunk sizes. Token lifetimes are not Talkdesk lifetimes. Doc dates are not product releases. Read the noun next to the number.

The Zoom sample also shows a placeholder token. The placeholder is not a secret you can use, and it is not a number to memorize.

Worked example

Make a two-column card: repeat, and confirm. Repeat only the four facts in the five-minute list, each with its page. Put license price and port numbers in confirm.

Quiz

1. The Zoom sample expires_in is 3599.

2. 90,000 customers means 90,000 SIP trunks.

Ecosystem

Sister pieces sit on the ecosystem page: the glossary, the mind map, the integration map, and the bridges.

  • expires_in — The field in Zoom's sample token response. The sample value is 3599.
  • Customer count — A company figure. Not a sizing input unless the page says so.

Config. Put the URL in the same row as the number.

Troubleshooting. A design spreadsheet that mixes these numbers is mixing a token, a doc date, and a customer count. Split the rows.

Bridge. The charts page uses repo counts, which are numbers this repository can recount.

Mind map, sister technologies, and future hooks live on the ecosystem page.

Sources and go deeper

Opened 2026-10. A row marked confirm has no link, because that page was not verified.

sources.json Markdown