You are here: CSP Developer’s Guide: Line Cards > 1 DS3 Information > Diagnostics
Overview
The DS3 card set has some internal diagnostic functions. You can also set the DS3 card to loopback diagnostic mode.
Diagnostics include:
• Detection of carrier group alarm
• Loss of frame
• Signal
• Carrier group alarm generation
Statistics for errors and alarms are gathered to support Request for Comment (RFC) 1407. Statistics can also be retrieved by the host using the Generic Report (0x46) message.
Loopback Diagnostics
Using the Loopback entity, the DS3 Configure/Query message (0x000F) loops the inbound DS3 stream back to the outbound DS3 stream. This message can also request the far end to go into loopback mode.
Follow the steps below to place a DS3 span into loopback mode.
1. Take the DS3 span out of service by using Assign Logical Span ID.
2. Use the DS3 Configure/Query message (0x000F) message to loopback the span.
Important! The Loop Timing Configure (0x4A) message is not supported because DS3 is not intended to be a loop timing source. You can get clock source timing off a T1 span or an external BITS source.