Cisco 2600 Series Operation Manual page 107

Table 10-1 MICA Module Port Numbers
MICA Bank
0 (left)
1
2
3
4 (right)
This relation can be expressed as:
port-number = (6 x bank-number) + modem-number
For example, the third modem (modem 2) in the second MICA module from the left
(bank 1) is assigned port number (6 x 1) + 2 = 8.
Some Cisco IOS commands identify ports by interface number (or line number or TTY
number, which are the same as the interface number) rather than slot and port number. The
interface number of a modem port is related to its slot and port number in the following
way:
interface-number = (32 x slot-number) + port-number + 1
This can also be expressed as:
interface-number = (32 x slot-number) + ((6 x bank-number) + modem-number) + 1
For example, if the module containing the modem in the last example is placed in slot 2,
the modem is assigned interface number (32 x 2) + ([6 x 1] + 2) + 1 = (32 x 2) + 8 + 1 = 73.
This is also the line and TTY number for the port. The modem in this position is always
assigned interface 73, whether or not there are other MICA modules in the digital modem
network module or other digital modem network modules in the router chassis. If you move
the MICA module to a different position in the digital modem network module, however,
or move the digital modem network module to a different slot in the router chassis, the
interface number changes.
Table 10-2 shows the range of interface numbers available in each router slot. Interface 0 is
automatically assigned to the console.
Port Numbers
0–5
6–11
12–17
18–23
24–29
Connecting Digital Modem Network Modules to a Network 10-5
Interface Numbering