Eltek R7111-L1, User Manual, Page: 6 / 62

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Introduce
R7121-L1/R7141-L1/R7111-L1 series are the low cost VoIP Solutions. This document describes the
usage of R7121-L1/R7141-L1/R7111-L1 (Analogue Telephone Adapter)
1.1 Overview
An Analogue Telephone Adapter, or R7121-L1/R7141-L1, is a device that allows one to connect a
normal PSTN telephone to the Internet in order to make or place telephone calls.
R7121-L1/R7141-L1 provides a direct analog interface for PSTN, PBX, fax machines, analog telephones,
and other devices that require an analog port.
1.2 Audience
This document is intended for system vendor who are using R7121-L1/R7141-L1 to build an Internet
telephony gateway or server application. It is assumed that the reader has the general knowledge of VoIP
applications and products.
1.3 Acronyms Table
Acronym: Full Name: Acronym: Full Name:
API Application Interface CODEC Coder / Decoder
ADC Analog to Digital Converter DC Direct Current
DAC Digital to Analog Converter DHCP Dynamic Host Configuration Protocol
DDNS Dynamic Domain Name System DNS Domain Name System
DTMF Dual Tone Multi Frequency MAC Media Access Control
FXS Foreign Exchange Station NAT Network Address Translation
WAN Wide Area Network PPTP Point-to-Point Tunneling Protocol
NTP Network Time Protocol RTCP Real-Time Transport Control
Protocol (also known as RTP control
protocol)
RTP Real-Time Transport Protocol SLIC Subscriber Line Interface Circuit
SIP Session Initiation Protocol URI Uniform Resource Identifier
STUN Simple Traversal of UDP through
NATs UDP User DSR-100gram Protocol
TCP Transmission Control Protocol VoIP Voice Over Internet Protocol
1.4 Introduction
This Analogue Telephone Adapter (R7121-L1/R7141-L1/R7111-L1) provides a total solution for
integrating voice-data network and PSTN.
The R7121-L1 Analogue Telephone Adapter (R7121-L1) support SIP VoIP Protocol. The R7121-L1
Analogue Telephone Adapter (R7121-L1) allows 1~2 lines analog voice and fax communication over a
traditional data communications/data networking digital Internet.