Juniper Networks ERX-705, ERX-1410, ERX-1440, ERX-700 Cabling the SRP I/O Module, Port Description

Cabling the SRP I/O Module ERX Edge Routers

4-7

Cabling the SRP I/O Module

The next step in cabling the system is to connect cables to your SRP I/O module. See Figure 4-3.

Note: The alarm function on the SRP I/O module is currently not implemented.

Cable connections to your SRP I/O module are divided into two sections: external timing ports and console ports. Table 4-2shows the specifications for each section.

Table 4-2SRP I/O ports

Port	Description
External Timing	• Two 3-pin wire-wrap posts for US external clock sources;
Ports	primary (A) and secondary (B)
	• Two BNC connectors for E1 clock sources; primary (A) and
	secondary (B)
Console Ports	• One 10/100Base-T Ethernet management port with an RJ-48C
	connector
	• One RS-232 port with a DB-9 connector for VT100 management
	access

External Timing Ports

Two external clock source input ports provide a method of ensuring that the system’s clock timing remains synchronized with the network’s system clock. The primary clock is labeled A; the secondary, redundant clock is labeled B. Use the connector type appropriate for your location:

•Two 75-ohm E1 2.048-Mbps inputs with BNC connectors

•Two 100-ohm T1 inputs with three pin wire-wrap connectors. Pins are labeled T (Tip), G (Ground), and R (Ring). We recommend using 26-AWG wire minimum.

Note: Use shielded cables to connect the external clock sources to the clock source input ports.