ADTRAN ISU 2X64 user manual Recommended Operating Protocols, DTE#2

Chapter 1.Understanding ISDN and the ISU 2x64

When the ISU 2x64 is used on an existing ISDN line that is not multipoint, with one SPID or no SPID numbers, additional con- siderations should be addressed. If DTE specific operation is desired, the ISDN line must be converted to multipoint operation (2 SPIDS). If not, the following applies:

1.If a single SPID is assigned, it must be entered under SPID

DTE#2.

2.When no calls are active, the first incoming call is always di- rected to DTE#2.

3.DTE#1 only accepts incoming calls when a call is active on

DTE#2.

4.Outgoing calls can be placed without restrictions from either port.

For applications involving only one SPID being used on a multi- point line, the SPID assigned must be entered under SPID DTE#2. For applications involving the S/T version (part number 1200.051L5 and 1200.051L6), no SPID(s) are used when the Euro ISDN or VN4 switch type is selected. The call will be routed to the appropriate port based on the directory number entered under the local directory number (LDN) prompt . See the section Setting the Terminal ID on page 32 for more detail on entering SPID numbers.

RECOMMENDED OPERATING PROTOCOLS

The ISU 2x64 supports a wide range of operating modes. Many combinations of circuit type, protocol, and data rate may be selected. However, only the combinations shown in Table 1-B are recommended. As noted in Table 1-B, all asynchronous rates sup- port flow control. Flow control is required when operating at 115200 bps using V.120, PPP, MLPPP, SAP, or BONDING proto- cols.

Table 1-B shows that a given data rate may be achieved by more than one protocol/rate adaptation selection. The table is orga- nized so that selections with lower throughput delay are nearer the top of the table for any given circuit type. Therefore, users should choose a protocol and rate nearer the top of the list for any given circuit type.

6 ISU 2x64 Dual Port ISDN Service Unit User Manual 61200051L1-1D