The Quad T1 and E1 Transceiver MCMs offer a high density packaging arrangement for the DS21352/DS21552 T1 Single-Chip Transceivers and the DS21354/DS21554 E1 Single-Chip Transceivers. Four silicon die of one of these devices is packaged in a Multi-Chip Module (MCM) with the electrical connections as shown in Figure 1. All of the functions available on the DS21352/DS21552 and DS21354/DS21554 are also available in the MCM packaged version however in order to minimize package size, some signals have been deleted. These differences are detailed in Table 1. This data sheet describes the electrical connections and the mechanical dimensions only. Please see the DS21352/DS21552 and DS21354/DS21554 data sheets for full details on all of the features and the operating characteristics of the device.