Faxing with SkySwitch

Last updated on March 7, 2025 at 4:26 PM

SkySwitch supports faxing with a SIP ATA on a best-effort basis only!

Fax machines rely on the analog representation of a digital signal (what you hear as a "fax tone"), and therefore, they are susceptible to deviations in the fax data transmission. In practice, this means that faxes are often interrupted by jitter and latency in the last mile (the portion of the call path between the switch and the end user's fax machine). This level of unreliability causes most VoIP service providers to avoid deploying faxes using SIP ATAs.

We strongly recommend that Resellers deploy faxing using the SkySwitch Instant Fax ATA.

Note: It is not possible in our system to have both services of calls and faxes to a single DID.

For more information, please view our DID Routing article found here.

Use of the Instant Fax ATA requires you to purchase a proprietary fax ATA from SkySwitch. To place an order, please go to the SkySwitch Store available from the Dashboard Menu.

It is not possible to Fax on SkySwitch with a BYOT Number. The DID must be active through SkySwitch in order to use any of our faxing methods.

Comparison of Fax Methods

	SIP ATA	Instant Fax ATA	Instant Fax Portal
Hardware	Any SIP Compatible ATA may be used	Proprietary ATA must be purchased from SkySwitch	No ATA required
Cost to Reseller	Requires Standard PBX User Seat Faxes incur standard Telco Usage charges	No PBX User Required. ATA must be purchased, and a monthly charge per ATA applies. Per minute Telco Services charge is applied.	PBX User is required, but for Fax Users without a device associated, there is no additional cost. Fax DID Add-On Charge Per minute Telco Services charge is applied.
Supports Fax-to-Email	No	Yes	Yes
Supports Email-to-Fax	No	No	Yes
Supports Standard Fax Machine	Yes, connected to ATA by RJ11 cable	Yes, connected to ATA by RJ11 cable	No, faxes are sent from Fax page of PBX User portal or email only. Faxes may be received by email or viewed from Fax Inbox of PBX User portal.
Supports Fax Delivery Notifications	No	Yes, delivery notifications are sent by email	Yes, delivery notifications are sent by email and inserted to PBX Fax Inbox page.
Reseller's Management UI	Managed from DID portal and separate Fax portal.	Managed from DID Portal.	Managed from DID Portal.
Reliability	Low	Medium to High	Medium to High

Note: We have found Fax ATA outbound faxes to devices with a Fax 'Stick' can be problematic and require configuration changes to the receiving fax machine for successful transmissions at times.

Comparison of Fax Methods

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