Texas has a $25 per-month (per-customer) tax exemption for internet access. Annual/quarterly/etc. packages are exempt for up to the $25/month over the applicable time period.
- Turn on the enable_taxclasses and require_taxclasses configuration values (Configuration | Settings | Edit Configuration | Billing)
- Go to Configuraton | Billing | View/Edit Locales and tax rates, scroll down to US - TX and click on "expand taxclasses"
- Enter "Access" and "Other" tax classes (or whatever labels you want)
- From the tax rate listing click on "Edit tax rates". Scroll down to US - TX again and enter the state sales tax rate (8.25%? varies by county?) for both tax classes. For the "Access" tax class, enter a $25 monthly exemption.
- If you already have package definitions in your system, edit them and assign them to the correct tax class.