OC3 broadband is the third Optical Carrier (OC) level carried on a Synchronous Optical NETworking (SONET) fiber optic network. The OC level is directly proportional to the data rate of the digital signal with each level representing approximately 51.84 million bits per second (Mbit/s).

OC3 speed is therefore 155.52 Mbit/s of which 148.608 Mbit/s is payload and 6.912 Mbit/s is overhead (including the path overhead). An OC3 line may also be known as a Synchronous Transport Module 1 (STM-1) line, which is the basic transmission rate of the Synchronous Digital Hierarchy (SDH) International Telecommunication Union Telecommunication (ITU-T) standard.

OC3 lines have the same speed as a Synchronous Transport Signal 3 (STS-3) line, which carries an electrical signal. The letter C (for concatenated) is appended to OC3 broadband when the signal is not multiplexed.

SONET SDH is currently the standard for optical telecommunications and will probably provide the data transmission infrastructure for telecommunications until at least the year 2030. It has significantly more bandwidth and flexibility over older telecommunications systems like traditional telephone lines.

In order to obtain OC3 service you will need to:

1. Obtain quotes from multiple providers on customized OC3 service packages.

2. Locate the available flat rates on standardized OC3 service packages.

3. Find any ongoing discounts or specials on OC3 services in your area.

Action Steps
The best contacts and resources to help you get it done

Get bids on broadband OC from competing providers

OC3 pricing tends to be highly flexible and you will frequently need to seek bids on a customized service package. Determine the specific needs of your business first and then ask each OC3 carrier what they would charge for that service.

I recommend: Complete this online form to receive a bid directly from an OC3 Internet provider. Your needs will automatically be sent to broadband OC vendors that match your criteria.

Find companies that offer a flat rate on OC3 Internet service

You may already be interested in a particular broadband OC carrier. You will usually be able to check the availability directly from the website by entering some location information.

I recommend: Use the service availability tool at US*Access. Enter your phone number for specific availability or your zip code for service to your general area.

Take advantage of current specials if you plan to purchase OC3

Many OC3 providers provide discounts to their customers, which are typically application service providers, content providers or large Internet Service Providers (ISPs).

I recommend: Look at the current specials at broadband.com. Their participating carriers also provide pricing options for both metered and tiered OC3 service.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  OC3 carriers should have a multiple location services representative whom you should work directly with when arranging OC3 service for multiple locations. This is because OC3 service is usually beyond the price range of businesses with only one location.
• •  OC3 service is categorized in three pricing categories: fractional, burstable and full. The transmission rate on burstable OC3 can be highly variable so it is vital that you determine the floor (lowest allowed speed) when considering this type of OC3 service.