> ## Documentation Index
> Fetch the complete documentation index at: https://docs.voxo.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Grandstream ATA

> Connect analog devices like fax machines to VOXO with a Grandstream HT8xx analog telephone adapter, and troubleshoot one that won't come online.

A Grandstream HT8xx analog telephone adapter (ATA) connects analog devices, such as a fax machine or an analog handset, to your VOXO phone service. The adapter sits between your network and the analog device and registers to VOXO as a phone line.

## Which model do I have

The HT8xx family differs by how many analog (FXS) ports each model has. Each port maps to one analog device.

| Model | Analog ports                                 |
| ----- | -------------------------------------------- |
| HT801 | 1 — for a single fax machine or analog phone |
| HT812 | 2                                            |
| HT814 | 4                                            |
| HT818 | 8 — for larger deployments                   |

<Tip>
  Some sites use one HT801 per fax machine so a single adapter failure only affects one machine.
</Tip>

## Connect the adapter

<Steps>
  <Step title="Connect the network">
    Plug an Ethernet cable from your network into the ATA's network port.
  </Step>

  <Step title="Connect the analog device">
    Plug your fax machine or analog phone into one of the phone (FXS) ports.
  </Step>

  <Step title="Connect power">
    Connect power. The adapter pulls its configuration from VOXO automatically once it is online.
  </Step>
</Steps>

Confirm the link light on the network port lights up when the cable is connected. A lit link light means the adapter has a working network connection.

## If the adapter does not come online

An ATA that never registers is almost always a network problem rather than a faulty unit. Before assuming the hardware is bad:

<Steps>
  <Step title="Test the port with a laptop">
    Plug a laptop into the same Ethernet port. If the laptop cannot get online, the port is the problem.
  </Step>

  <Step title="Try a different port">
    Move the cable to a different switch or router port.
  </Step>

  <Step title="Try a new cable">
    Swap in a known-good Ethernet cable.
  </Step>

  <Step title="Check the link light">
    Confirm the link light on the ATA illuminates.
  </Step>
</Steps>

**Contact support** if the network port passes a laptop test and you have tried a different port and cable, but the adapter still has no dial tone or fax on any connected device.