Nortel Networks 553-3001-211 manual QPC513 Enhanced Serial Data Interface card Page 855

QPC513 Enhanced Serial Data Interface card Page 855 of 894

Applications

The QPC513 Enhanced Serial Data Interface card is used any time that a high-speed, fully synchronous serial data communication channel is needed. The ESDI card is typically used to connect to the following:

•Meridian Mail

•A host computer using Meridian Link

•An auxiliary processor

The system processor transfers data to the ESDI card in blocks consisting of 1 to 128 eight-bit octets. Each block is processed in accordance with the LAPB subset of the HDLC protocol and is transmitted serially to the output port.

In receive mode, the EDSI card receives data serially from the input port packages in LAPB information frames. After determining that the block is error-free, the ESDI card supplies the data to the system processor as a block.

The ESDI card serial ports terminate on the card front panel. Figure 183 on page 856 shows the typical ESDI card connections in a system.

Circuit Card Description and Installation