---
title: Business Phone System Guides | PBXflex
description: Plain-language guides to business phone systems: what a cloud PBX is, what one costs, and how auto attendants, call queues, texting and fax work.
url: https://www.pbxflex.com/guides
---

# Business phone systems, explained plainly

Short answers first, then the detail. Written for the person who has to choose a phone system for the office, not for telecom engineers.

- [What is a PBX?](https://www.pbxflex.com/guides/what-is-a-pbx.md): What PBX stands for, what a PBX does, the three types (traditional, IP and cloud), how PBX and VoIP fit together, and a checklist for moving off an old system. Updated October 10, 2026.
- [How much does a business phone system cost?](https://www.pbxflex.com/guides/business-phone-system-cost.md): Every line on a business phone bill, from the plan to the "regulatory recovery" fee, with PBXflex's own published usage rates and one-time costs. Updated October 10, 2026.
- [A2P 10DLC registration, step by step](https://www.pbxflex.com/guides/10dlc-registration.md): What A2P 10DLC means, the brand and campaign registrations carriers require, what you submit, how STOP and HELP work, and how long review takes. Updated October 10, 2026.
- [IRS fax numbers by form, with the source for each](https://www.pbxflex.com/guides/irs-fax-numbers.md): The IRS fax numbers for Forms 2848, 8821, 2553, SS-4, 4506-T and 911, by state, each linked to the irs.gov page it came from. Plus when to submit online instead. Updated October 10, 2026.
- [Free fax cover sheet templates, and how to fill one in](https://www.pbxflex.com/guides/fax-cover-sheet.md): Three free fax cover sheet PDFs (general, confidential and IRS), with a plain guide to what each field means and how to count the pages. Updated October 10, 2026.

## Contact

- Email: hello@pbxflex.com
- Phone: (877) 575 - 9527
- Address: 1001 Wilshire Blvd, Los Angeles, CA 90017
- Sign up: https://pbxflex.app/auth/sign-up