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1. Trunk Settings

See the following topics:

Line Build Out settings

Line Build Out is a means of simulating additional cable length between a T-1 trunk’s transmitter and the far-end receiver. This is done in case the signal being transmitted is too strong. When the phone company deploys T-1 lines, each cable runs for 6000 feet before going into a repeater to boost the T-1’s signal strength. When the T-1 line reaches its final destination, the final span will generally not be exactly 6000 feet. Instead, the span length will be somewhere between 0 and 6000 feet and average 3000 feet. If the final span is much less than the average, the final repeater’s receiver will be much too close to the customer’s transmitter. The customer’s transmitter signal will be too strong for the repeater to handle.

There are three FCC sanctioned signal levels that the customer can be asked to provide. They are as follows:

The customer provisioning letter will state what the Line Build Out (LBO) should be set at. If the provisioning letter does not give an LBO value, then use the 0 dB default.

Wave also provides a -22.5 dB LBO value (12.5 percent power). This is not sanctioned by the FCC and should never be used with the PSTN. However, for private networks where the far end is only a few feet away, this might be useful.

The default, 0 dB, is the most common signal level for connection to the carrier. If line build out is set incorrectly, the carrier may detect errors, prompting an SNMP yellow alarm and a yellow LED on the T-1 module. If you see such indicators and cannot determine another cause, try changing the Line Build Out setting.

Note:  The yellow alarm will occur only in case of extreme errors, such as one in 100 bits being bad.

For more information, refer to Customizing transmit and receive signal settings.

Trunk timing values

Customizing transmit and receive signal settings

Customizing transmit and receive signal settings

In the event that the standard Line Build Out settings are not correct for your T-1 configuration, you can customize the following Line Build Out settings. For configuration instructions, see Configuring digital trunk card or module settings.

Caution!  Do not modify line build out settings unless you work with your T-1 provider to determine appropriate settings.

Note:  If you find a “canned” cable length that works well, these settings will be grayed out and ignored. If you specify that you are using a Custom Cable, these settings will be used.

This setting determines whether automatic receive equalization is enabled or not. If this is enabled, the Wave T-1 framer chip automatically and intelligently boosts the signal coming in to the optimal level for pulse detection. This is called automatic equalization. In this mode, the Wave system can accommodate an incoming signal strength range between -36 and -0 dB.

If the Enable Receive Equalizer check box is disabled, a fixed (non-intelligent) 6 dB boost is added to the receive signal. If this box is disabled, the Receive Input Threshold list box is then enabled.

You enable this when you disable the Enable Receive Equalizer check box. When automatic receive equalization is turned off, the framer chip recovers signals by comparing directly to a Receive Input Threshold. If the signal is lower than the threshold, the chip senses a 0. If the signal is higher than the threshold, the chip senses a 1. If the signal is exactly the same as the threshold, the result is unpredictable.

1.36 volts is the default threshold level. T-1 signals generally range between 0 and 3 volts in amplitude. However, if a signal is extremely weak, you can set the receive threshold to as little as .22 volts.

Setting the Receive Input Threshold attempts to reduce the input threshold value to accommodate a small input signal.

Note that there are two problems with disabling the automatic equalizer. First is that the Wave system cannot adjust for dynamic changes in the signal strength of the T-1 line with the fixed boost given by the T-1 framer chip. Second, you must try to guess what the optimal input threshold level is. Generally, the automatic equalizer can determine the optimal input signal level better than you can guess the input threshold level.

This field allows you to input raw data to directly determine four points on the shape template of the T-1 pulse that is transmitted. Any changes to this field can easily cause the far-end to be unable to receive the T-1 signal sent by the Wave system. Do not modify this field unless specifically advised to do so by a Vertical Communications Customer Service representative.

The following table describes the configurable DSX parameters.

Trunk timing values

You can find the Trunk Timers in the Trunk Configuration applet. Refer to T-1 trunk timing values for information about timing values for T-1 trunks.

T-1 trunk timing values

The following table describes the different types of inbound T-1 Trunk timers for the E&M Wink Start and E&M Immediate Start signaling types.

The following table describes the different types of outbound T-1 trunk timers for E&M Wink Start and E&M Immediate Start signaling types.

The following table describes the different types of inbound trunk timers for signaling type ground start.

The following table describes the different types of outbound trunk timers for signaling type ground start.

The following table describes the outbound trunk timers for ISDN PRI.

Analog trunk timing values

The following table describes the different types of inbound analog trunk timers for loop start and ground start signaling types.

The following table describes the different types of outbound analog trunk timers for loop start and ground start signaling types.