Cisco 3825 Hardware Installation Guide - Page 161

Chapter 9 Connecting Digital Modem Network Modules Adding 6-Port MICA Modules to a Digital Modem Network Module Each modem in a digital modem module is also assigned a port number in the range 0 to 29. Modems in the left MICA module (as viewed from the rear of the router), bank 0, are assigned port numbers 0 to 5. Additional MICA modules, if present, are assigned port numbers as follows: 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 is 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 9-1 shows the range of interface numbers available in each router slot. Interface 0 is automatically assigned to the console. Table 9-1 Digital Modem Network Module Interface Numbering Slot Number 0 1 2 3 4 5 6 Interface Numbers 1-30 33-62 65-94 97-126 129-158 161-190 193-222 Adding 6-Port MICA Modules to a Digital Modem Network Module You can add modems to a digital modem network module, in groups of six, by installing additional 6-port MICA modules, up to a maximum of five MICA modules (30 modems). MICA modules are manufactured with a polarization notch to ensure proper orientation, and alignment holes that fit over guide posts to ensure proper positioning. (See Figure 9-2.) OL-2485-20 Cisco Network Modules Hardware Installation Guide 9-3