Analogue Telephone Adapter Cisco ATA 191, 2-port handset-to-Ethernet, SIP, G.711/G.726/G.729, T.38 fax

The Cisco ATA 191 is a compact 2-port analogue telephone adapter that connects traditional handsets, fax machines and paging devices to IP networks via an Ethernet interface. The unit supports SIP signalling and common voice codecs — G.711μ/a, G.726 and G.729A/ab — plus T.38 fax relay for reliable fax transmission over packet networks. Designed for small offices, branch locations and cloud-based UC deployments, the adapter provides secure management and interoperable network protocol support while preserving existing analogue equipment investments.

Advantages

The adapter delivers a small form factor and low power footprint while offering enterprise-grade security with AES encryption, HTTPS and SSH management. It supports a broad set of network protocols including TCP/UDP/RTP/HTTP/ARP/RTCP/ICMP/LLDP and can be managed via SNMPv3 for integration into monitoring systems. T.38 fax relay and multiple voice codecs ensure compatibility with legacy terminals and modern SIP-based PBX or UCaaS services. The device includes a manufacturer-limited 1-year hardware warranty and is suitable for environments where straightforward migration from analogue to IP telephony is required.

Suitable for

• Connecting traditional desk phones to a SIP-based VoIP network
• Enabling fax machines to operate over IP using T.38 relay
• Small office or branch deployments with limited space
• Integrating analogue paging systems into an IP audio environment

Key specifications

• Ports: 2 analogue FXS ports and 1 Ethernet 10/100 Mbps port
• Signalling: SIP
• Supported codecs: G.711μ/a, G.726, G.729A/ab
• Fax support: T.38 fax relay
• Network protocols: TCP, UDP, RTP, HTTP, ARP, RTCP, ICMP, LLDP
• Management: SNMPv3, HTTPS, SSH
• Security: AES encryption support for secure voice and management
• Physical dimensions: 100 × 100 × 28 mm; weight: 132.1 g
• Power: low-power compact design (external power adapter)
• Warranty: 1-year limited hardware warranty

How to use

Connect analogue handsets or a fax machine to the adapter's FXS ports and attach the Ethernet port to your network switch or router. Configure SIP account settings on the device web interface or via your SIP provider/UCaaS control panel. Verify codec and fax settings (enable T.38 if required) and confirm network parameters such as DHCP or static IP, DNS and gateway. Use SNMPv3 or the HTTPS/SSH management interfaces for integration into existing monitoring or configuration workflows. After provisioning, test voice calls and fax transmissions to confirm interoperability with your SIP infrastructure.

Usage recommendations

For reliable voice and fax performance, place the adapter on a stable network segment with sufficient bandwidth and QoS enabled for voice traffic. Ensure the SIP server and any NAT traversal settings are configured correctly; enable T.38 on both the adapter and your SIP infrastructure when using fax machines. Keep device firmware up to date and restrict management access to trusted hosts or management VLANs using HTTPS, SSH and SNMPv3 to maintain security.