You are here: CSP Developer’s Guide: Overview > 5 Layer 4 Call Control > Cross Connections
Using the Cross Connect Channel or the Cross Connect Span message, the host connects two physicalchannels or spans. Both spans must already have a Logical Span ID. Excel recommends taking both ends of the connection out of service first. When either of these messages are used, the connection is made regardless of any line or trunk configurations or formats currently set.
Cross Connect Channel
Connect the data paths of the two channels. Both Channel A and Channel B should be out of service, except when cross connecting T1 and E1 channels. No signaling information can be used to detect either channel releasing. The host must use the Cross Disconnect Channel message to tear down the connection.
Cross connecting T1 and E1 channels causes automatic PCM conversion (A-law/µ-law). By default, channels on T1 spans are µ-law, and channels on E1 spans are A-law. To disable conversion, configure both channels with the same format by using the PCM Encoding Format Configure message. You must disable conversion when you are connecting through an ISDN D channel.
Cross Connect Span
Connect all data paths on Logical Span ID A to data paths on Logical Span ID B. You cannot cross connect a T1 span with an E1 span without PCM conversion. Multi-frame synchronization is not maintained between two cross-connected spans.
Cross Disconnect Channel
Disconnect the data paths of the specified channels.
Cross Disconnect Span
Use the Cross Connect Span message to disconnect all data paths of two spans that were previously connected.