Grandstream’s HT series of Analog Telephone Adapters (ATAs) offer a ton of features at an affordable price point. They are trusted and deployed by some of the world's largest service providers. The HT704 is a 4-port FXS, with 10/100 Mbps ethernet and no router. It supports up to 4 SIP accounts.
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EOL NOTICE: Although this unit is certified, we recommend Grandstream's newer HT814 for new installations.
Firmware
Update to the latest firmware for your HandyTone before connecting to our service. You can download the current production release from the link above. Once downloaded, you'll navigate to "Advanced Settings" and click the "Upload from Local Directory" button. Select the file you downloaded from Grandstream's website, and then click "Apply" once this has completed your device will reboot. You can then move on to the steps below.
SIP Settings
Select "Profile 1" from the primary menu, and and configure the following options for your SIP settings. The SIP server setting is a bold setting at the top of the page, and it is followed by the other two options in the following italic section. The "Request Routing ID" setting is near the top of the italic section and the "Allow Incoming" section is below the large white box for "Trusted CA certificates."
- Primary SIP Server: sip.t38fax.com:5080
- NAT Traversal: Keep-Alive
- Use Request Routing ID in SIP INVITE Header: Yes
- Allow Incoming SIP Messages from SIP Proxy Only: Yes
Network Settings
Scroll down and configure the following options:
- Register Expiration: 5
- Local SIP Port: 5080 ⓘ - If you have more than one device at a site, each device at a site should have a unique port, such as 5081, 5082, etc..
- Allow Incoming Packets from SIP Proxy Only: Yes
 
Feature Settings
Scroll down and configure the following options, grouped together below the Ring Tone dropdowns:
- Disable-Call-Waiting: Yes
- Disable-Call-Waiting-Caller-ID: Yes
- Disable-Call-Waiting-Tone: Yes
 
Fax Settings
Configure the following T.38 specific options near the bottom of the page:
- Fax Tone Detection Mode: Callee
- Jitter Buffer Type: Fixed
- Jitter Buffer Length: High
- Disable Line Echo Canceller (LEC): Yes
- Disable Network Echo Suppressor: Yes
Call Routing
NOTE: For simplicity, this section features a screenshot from a different ATA, but configuration is identical apart from how many ports are on the unit.
Primary Line
From the top menu bar, select "FXS Ports." To set up the first line with your T38Fax trunk, insert your Trunk ID and password into the first port. Saving the page will blank out the password field.
In the image below, the fields boxed in red indicate changes necessary for primary line: this is where you enter your SIP trunk's username and password ⓘ.
Secondary Line
It's possible to attach multiple fax machines, each with its own phone number, to a single HandyTone ATA using a single T38Fax trunk. You'll need to assign at one additional DID to this trunk for these instructions to work.
To add an additional line, set the primary line's Hunt Group to "Active" and set the secondary line's Hunt Group to the primary line's port number (in this case, 1). Set the Request URI Routing ID on the secondary line to the additional DID you purchased. Here the trunk ID is 16467511475 and the extra DID is 12013562252. Outbound calls from this trunk will show the extra DID, 12013562252, as the caller ID; inbound calls to 12013562252 will route to port 2 instead of port 1. Port 1 will likewise service 16467511475. Both ports can even be on a call at the same time!
In the image below, the fields boxed in green indicate changes necessary for registering a secondary line.
Fax Machine
Finally, configure your fax machine to work properly with your Power-T.38 SIP Trunk. Review our Recommended Fax Machine Settings for details.