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Reference.org
Basic Rate Interface
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<p>Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an <a href="/facts/Integrated_Services_Digital_Network/zcV99rUb">Integrated Services Digital Network</a> (ISDN) configuration intended primarily for use in <a href="/facts/Subscriber_line/rSRfLPaq">subscriber lines</a> similar to those that have long been used for <a href="/facts/Plain_old_telephone_service/7uEc2wFY">voice-grade telephone service</a>. As such, an ISDN BRI connection can use the <a href="/facts/Plain_old_telephone_service/7uEc2wFY">existing telephone infrastructure</a> at a business. </p><p>The BRI configuration provides 2 data (bearer) channels (<a href="/facts/B_channel/1QoQqrcz">B channels</a>) at 64 kbit/s each and 1 control (delta) channel (<a href="/facts/D_channel/MRGdbNlU">D channel</a>) at 16 kbit/s. The B channels are used for <a href="/facts/Human_voice/RPzaPWwh">voice</a> or user <a href="/facts/Data/AUBFN97o">data</a>, and the D channel is used for any combination of data, <a href="/facts/Signaling_(telecommunications)/6d4zgUj7">control signaling</a>, and <a href="/facts/X.25/yaGPqw2Y">X.25</a> packet networking. The 2 <a href="/facts/B_channel/1QoQqrcz">B channels</a> can be aggregated by <a href="/facts/Channel_bonding/3BE3qHDT">channel bonding</a> providing a total data rate of 128 kbit/s. The BRI ISDN service is commonly installed for <a href="/facts/Residential/EUBWCrmD">residential</a> or small business service (ISDN <a href="/facts/PABX/eLWvlhzs">PABX</a>) in many countries. </p><p>In contrast to the BRI, the <a href="/facts/Primary_Rate_Interface/tNSdVs55">Primary Rate Interface</a> (PRI) configuration provides more <a href="/facts/B_channel/1QoQqrcz">B channels</a> and operates at a higher <a href="/facts/Bit_rate/ppUNMmVd">bit rate</a>. </p>