Overview

PCI Ultra T1/E1 have 3 clock options to choose. With internal clock option the transmit section is clocked using an internal oscillator. For recovered clock option The transmit section is clocked using the clock derived from the received signal. If no received signal is present the internal clock is used. An external clock can be provided at the SMB input of the Cards or Dual USB Units. A TTL or CMOS level is acceptable. Apply a 1.544 MHz clock for T1 or a 2.048 MHz clock for E1.

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Description

Internal Clk:

The transmit section is clocked using an internal oscillator. 1 ppm is provided, when this option is selected, the internal clock is also provided at the Ext Clk SMB connector.

Recovered Clk:

The transmit section is clocked using the clock derived from the received signal. If no received signal is present the internal clock is used. When this option is selected, the recovered clock is also provided at the Ext Clk SMB connector.

External Clk:

An external clock can be provided at the SMB input of the Cards or Dual Laptop Units. A TTL or CMOS level is acceptable. Apply a 1.544 MHz clock for T1 or a 2.048 MHz clock for E1. The Ext Clk at the SMB connector may be an input or an output depending on the clock settings. For Internal and Recovered clock options, the SMB connector provides an output clock. For External Clock option, the SMB connector provides for an externally provided input clock.