et up a path on Basic signalling protocols. By regular monitoring of an installation, Rate connections, and then perform a transmission test, also have potential trouble can be spotted before it gets too serious. Connec- protocol support. This support however is only intended to perform tion to the network is normally made at a protected high impedance a functional test and does not usually include the ability to decode monitoring point, or by a bridge through the tester interface. or display protocol events. Introduction to cellular radio 61/21 61.5.7.1 Inter-operability testing SAPI=0 (CCP) TEI=66 Time: 12.30:00:1200 Inter-operability testing is designed to prove whether two ISDN 1869824 Q921: 0 85 AC C4 devices or services can and will work together to specification. Any PD=08 UCC REF=018 ISDN product has to be tested for inter-operability with any other M 05 SETUP ISDN product that it may have to communicate with. A maxim in I 04 Bearer Capability Len=2 inter-operability testing is that the commutative law does not apply. 58 Coding Standard CCITT In other words, if A interoperates with B and B interoperates with Transfer Capability Unrestricted C, A does not necessarily interoperate with C. ISDN products must 90 Transfer Mode Circuit be tested for interoperability and conformance at every major revi- Transfer Rate 64Kbit/s sion. 118 Channel Identification Len=1 Interface Implicity Identified 8A Interface Type Basic 61.5.7.2 Conformance testing Indicated Channel Exclusive Channel Indicator Not D-Channel Channel Selection Conformance tests are usually run automatically in a long series of 70 Called Party Number short, very specific tests with pass/fail results provided along the way. Many ISDN providers, such as telecommunication ministries, 80 Type Unknown require conformance testing before a given product or service can Numbering Plan Unknown be operated on their networks, a given product or service is usually Address Digits 0048885030 Q931: 0801 18 03 04 02 88 90 18 01 8A70 only ever tested once for conforma