Chapter 15 Integrated Services Data Network (ISDN)Page 15-10 UNIVERGE NEAX 2000 IPS Request for Proposal (RFP) Reference GuideIssue 6ISDN PRI SpecificationsDTIThe Digital Trunk Interface (DTI) interfaces the PBX directly to 24/30-channel PCM transmission line.The DTI has the following functions.For 24DTI:• Two Directory numbers, each with a SPID• Unipolar/Bipolar Conversion (AMI/B8ZS Format)• Alarm Detection/Insertion• Digital PAD on Voice Signal Transmission• Loop-Back Test (Local/Remote Loop Back)• Cyclic Redundancy Checking (based on ITU-T Rec. G704)For 30DTI:• Unipolar/Bipolar Conversion (HDB3 Format)• Alarm Detection/Insertion• Digital PAD on Voice Signal Transmission• Loop-Back Test (Local/Remote Loop Back)• Cyclic Redundancy Checking (based on ITU-T Rec. G704)For connections of 24DTI and transmission line, twisted-pair cable can be used. For connection of30DTI and transmission line, either coaxial cable or twisted pair cable can be used.DCHThe D-Channel Handler (DCH) provides the D-Channel signaling interface through the DTI to an ISDNexchange, and it is responsible for signaling between the PBX and the ISDN exchange under control ofthe system MP.PRTThe Primary Rate Interface Trunk (PRT) provides the ISDN Primary Rate Interface (1.5 Mbps PCM-23B+ D/2 Mbps PCM-30B + D) and a built-in D-Channel Handler (DCH). The PRT has the followingfunctions.For 24PRT: Unipolar/Bipolar Conversion (AMI/B8ZS Format) Alarm Detection/Insertion Digital PAD on Voice Signal Transmission Loop-Back Test (Local/Remote Loop Back) Cyclic Redundancy Checking (based on ITU-T Rec. G704)For 30PRT: Unipolar/Bipolar Conversion (HDB3 Format) Alarm Detection/Insertion Digital PAD on Voice Signal Transmission Loop-Back Test (Local/Remote Loop Back) Cyclic Redundancy Checking (based on ITU-T Rec. G704)
