# Overview

Line module slots are located in the front of each ERX chassis, while I/O module slots are located in the rear. See ERX Overview for front and rear views of ERX routers.

In ERX14xx models, modules mount vertically in a chassis with 14 slots. In ERX7xx models and ERX310 Broadband Services Routers, modules mount horizontally in a chassis with 7 slots and 3 slots, respectively. See Figure 16.

Figure 16: Orientation of Line Modules in ERX Routers

For details about available line modules and compatibility between line modules and SRP modules, see the ERX Module Guide.

## Slot Groups

The slots in the ERX1410 router and ERX7xx models are divided into groups. The number of groups and number of slots per group depend on the system.

There are no slot groups in the ERX1440 or the ERX310 router. In the ERX310 router, slot 0 contains the SRP module and slots 1 and 2 each contain a line module.

### Slot Groups for the ERX1410 Router

A slot group in the ERX1410 router comprises three adjacent chassis slots. The groups for the ERX1410 router consist of the following slots (Figure 17):

- Slot group 1—Slots 0 through 2
- Slot group 2—Slots 3 through 5
- Slot group 3—Slots 8 through 10
- Slot group 4—Slots 11 through 13

Slots 6 and 7 are reserved for the SRP modules.

Figure 17: ERX1410 Slot Groups

### Slot Groups for the ERX7xx Models

A slot group in an ERX7xx model comprises one slot or two adjacent slots. The groups for an ERX7xx model consist of the following slots (Figure 18):

- Slot group 1—Slots 2 and 3
- Slot group 2—Slot 4
- Slot group 3—Slot 5
- Slot group 4—Slot 6

Slots 0 and 1 are reserved for the SRP modules.

Figure 18: ERX7xx Model Slot Groups

## Combinations of Line Modules In Slot Groups

For information about combinations of line modules in slot groups, see JunosE System Basics Configuration Guide, Chapter 6, Managing Modules.

## OC48 Line Modules

The ERX1440 router with the SRP-40G+ SRP module supports OC48 line modules. Other ERX routers do not support OC48 line modules.

An OC48 line module spans two slots in an ERX1440 router. You can install this line module only in slots 2–3 and slots 4–5. Other slots in the system do not support this line module.

The corresponding OC48 Frame APS I/O module spans only one slot. Install the I/O module in the lower of the slots (either slot 2 or slot 4) that the line module spans.

## GE-2 Line Modules

The ERX1440 router with the SRP-40G+ SRP module supports GE-2 line modules in all slots; however, full bandwidth is delivered only when the line module is in slot 2 or slot 4. The line module can be used with other SRP modules, but maximum line performance will not be achieved.

The ERX310 router with the SRP-SE10G SRP module supports GE-2 line modules in both slots (1 and 2). Maximum line performance is achieved in either slot.

Other ERX routers do not support GE-2 line modules.

## Managing Modules Using the Software

For information about software procedures associated with replacing and managing modules, see JunosE System Basics Configuration Guide, Chapter 6, Managing Modules.

## Hot-Swapping Modules

All ERX routers support hot-swapping of modules. Hot-swapping enables you to add or remove a module without powering down the system.

## Protecting Modules and Slots

Each ERX chassis has an ESD (electrostatic discharge) grounding jack. See Table 3 for locations. To prevent damage from electrostatic discharge, connect an antistatic wrist strap to the jack when handling components.

Figure 19: Connecting the Wrist Strap to the ERX310 Router (Rear)

Table 3: Grounding Jack Locations

E Series Router | Location
--- | ---
ERX14xx models | Front: inside front bezel in lower-left corner Rear: upper-right corner
ERX7xx models | Rear: lower-right corner
ERX310 router | Front: lower-left corner Rear: lower-right corner

To protect the modules and slots when installing modules, observe the following guidelines:

| Caution: When handling modules, use an antistatic wrist strap connected to the router's ESD grounding jack. This action helps to protect the module from damage by electrostatic discharge.

| Caution: Always handle the module by its edges. Do not touch the components, pins, leads, or solder connections.

| Caution: If you meet strong resistance when attempting to seat the module using the ejectors, remove it from the chassis and confirm that the slot is designed to hold the module. Then verify, if applicable, that the module matches its corresponding module (I/O module or line module). Also, be sure that you have aligned the top and bottom edges in the correct matching tracks.

| Caution: Be sure to cover every empty slot with a blank filler panel to protect the system from dust or other foreign substances and to ensure proper system cooling.

| Caution: Do not discard the antistatic bag. When a module is not in use, store it in an antistatic bag.

## Order of Installation

Before you attempt to install or replace a line module (inserted in the front of the chassis), make sure the corresponding I/O module (inserted in the rear of the chassis) is already in place. The slot diagnostics run when a line module is installed in a chassis slot. If the corresponding I/O module is not present, the diagnostics fail, and you need to remove and reinsert the module.

## Required Tools and Safety Items

You need the following tools to install a line module:

- A No. 2 Phillips screwdriver
- An ESD wrist strap