A-8 APPENDIX A: PROVISIONING YOUR ISDN LINE
■The SPID numbers must be unique. The
■If you request ISDN service from a Northern Telecom
Area code +
■The TID can be any number from 0 to 62, but needs to be unique so that the SPIDs are also unique. This format applies when the switch is running Custom and
■If you order AT&T 5ESS ISDN services, choose either a Type A or Type E terminal. The Type E terminal is preferable because it is for data only.
■Do not request supplementary services, such as autohold or conference, because a SuperStack II bridge/router does not support them.
NT1s and Power North American telephone companies require an NT1 and a power
Suppliessupply for every ISDN line. Your service provider or telephone company can provide you with an NT1 and power supply for a small monthly fee. However, you may prefer to purchase it from an ISDN equipment vendor. The NT1 and power supply may come in a single, standalone box or the two may be in separate units. In this discussion, the two units together are referred to as an NT1.
Telephone companies in North America use two kinds of NT1s, differentiated by the data encoding scheme used in transmitting data between the NT1 and the telephone company’s equipment. The two data encoding schemes are 2B1Q (two bits mapped into one quaternary symbol) and alternate mark inversion (AMI). The 2B1Q scheme is the dominant method in use today. The AMI scheme is older and rarely used.
Two power sources are available from an NT1 for CPE equipment. An ISDN telephone uses one power source. The SuperStack II bridge/router does not use either source. Instead, it detects the presence or absence of phantom power and can determine whether or not a telephone cord is plugged in.
