Drop and Insert Mode
Drop and Insert mode combines the features of CSU mode and Mux mode. The DSX-1 equipment port is used for some of the T1 timeslots and data bus A is used to pass other timeslots to some DIU 21xx module(s). Since the CSU cannot control the transmit data rate of the DSX-1 equipment, the CSU is usually configured to recover transmit clock from the DSX-1 datastream (THRU timing).
Drop and Insert mode is established by selecting A, D&I NET for the DIU bus option. When this is done, a new option field appears in the Configuration Menu, beneath the PRM field, as shown below:
Select D&I DSOs Field
D&I DS0s (1,-,24)
____________ G) Alarm ENABLE
This field is used to select the timeslots for data use. Any timeslots shown in this field will be placed on data bus A for use by a DIU 21xx module. The DSX-1 equipment will receive a framed all-ones signal in those timeslots, making them appear busy to a PBX. Timeslots not listed in this field are allowed to pass unmodified to the DSX-1 equipment.
In addition to the T1 CSU functions, the NCC 2020 is also a node controller. The Node Administration Menu, and submenus beneath it, are used to configure site information, access passwords, and modem information.
Node Administration Menu
The Node Administration Menu is accessed by selecting “O” on the NCC 2020 Main Menu. Figure 3-4 shows the options presented.
Most of the commands on the Node Administration Menu are documented in Table 3-5 below.
Verilink NCC 2020 User Manual