If you are considering activating Power-T.38 service, we strongly recommend you take advantage of our no-risk, no-commitment free trial. Sign up online at your convenience, and your account will be instantly provisioned with a temporary local phone number (you’ll be able to select a different number la...

Please complete our Letter of Agency (LOA) form to submit your port order. Instructions are included on the first page of the form. In addition to the signed Letter of Agency (LOA), "Proof of Ownership" documentation is required to submit a port order. To establish valid Proof of Ownership of the numbers...

It's worth clarifying what usernames and passwords we use, so that you can be sure you're using the right credentials in the right context. There are two aspects to our service:  Our Power-T.38 SIP trunks Our customer self-service portal It's possible to have usernames and passwords for each...

The traditional port for SIP messages is 5060, but we recommend you use port 5080 whenever possible. The simple reason is that by running on port 5080, you hide the traffic from routers and firewalls that might try to "help" you by modifying the SIP signaling but often just end up breaking things....

SIP ALG Many routers, firewalls and even some modems come with a feature called SIP ALG that modifies SIP packets as they pass through the networking device. This feature should in theory make it easier for SIP calls to work through NAT but, especially for Fax over IP, it is often implemented incompletely. You ca...

We maintain an official compatibility list where we enumerate devices that have been tested and proven to work reliably with our service. A 'Certified' device means we have worked directly with the manufacturer and a formal, official interop test has been done between our companies. Devices we have teste...

The ECM Self Test You can use our ECM Self Test to send yourself a fax that reports your current fax settings. The fax page will tell you if you have ECM enabled and your transmission speed will be listed under "SignalRate", as shown below. We recommend the following settings: SignalRate: 14,400bps...

Login to your Self-Care portal at https://my.t38fax.com/. You can see your call records in Reports -> Transactions. Simply choose a time frame, then click the "Search" button.  

ECM stands for Error Correction Mode. In this mode, fax pages are sent in blocks and for any block that fails the error check the receiver will ask the sender to send it again until all blocks have been received successfully. ECM automatically detects and corrects errors in the fax transmission process that are som...

In order to dial out of our service, calls must be made in accordance with the North American Numbering Plan (NANP) system. For example, calls within the USA must use 11 digit dialing, which means 1 plus the area code and the remaining seven digits. For example: 1-215-825-8790.

We typically recommend completely disabling SIP ALG (Application-level Gateway) and inbound NAT rules, allowing us to take care of that for you. As long as you have an active SIP registration you should be permitted to send and receive faxes. We do far-end NAT traversal. What that means is that when you contact us...

All of the ATAs listed in our interop guides have passed our QA tests, but here are three popular two-port models with comparable capabilities: Grandstream HT812 Polycom OBi302 Cisco ATA192-MPP

Of course you can keep your current phone number(s)! That's one of the advantages of fax in the first place - the number never changes. Bring as many local phone numbers (DIDs) and toll free phone numbers (TFNs) as you like when you sign up. The process of redirecting the numbers away from your current carrier...

Our service supports the standard SIP/T.38 protocol. The major supplier in this arena is Dialogic, and we are proud to support Dialogic's SR140 host-based Fax Over IP (FoIP) engine.The SR140 product is embedded into a large number of Fax Server products such as: HylaFAX Enterprise GFI FaxMaker Imecom Fa...

Here are some links to walk you through the process of setting up with T38Fax, in approximately the order you'll want to read them. Pricing Model Popular ATAs Free Trial Signup - If you're planning on porting in, choose a temp number for your trunk. Implementation Guides - Some are also linked from the po...

How Number Forwards Work When setting up a call forward, you will need to specify two numbers: the forwarding number, and the forward destination. The carrier currently in possession of the forwarding number (the forwarding carrier) needs to set up the forward. Callers will dial the forwarding number (leg A), and ...