Nortel Networks 553-3001-211 manual 860 of 894 QPC841 Quad Serial Data Interface card

Page 860 of 894 QPC841 Quad Serial Data Interface card

Functional description

The QPC841 Quad Serial Data Interface card contains all the logic for four asynchronous serial ports, including the baud rate generators. These serial ports are directly accessed by the system processor using memory reads and writes.

The QPC841 Quad Serial Data Interface card contains four universal asynchronous receiver/transmitters (UARTs) and the logic necessary to connect the UARTs to the system processor bus. See Figure 185 on page 861. The other logic on the card consists of four baud rate generators, four RS-232-C driver/receiver pairs, and the jumpers and logic needed to configure the UARTs.

The address select switches and logic on the card always address the UARTs using two pairs of addresses: 0 and 1, and 2 and 3 through 15 and 16. The pairs do not need to be consecutive. Other switches on the board determine the baud rate for each individual port and whether the port is configured to talk to a terminal (DTE equipment) or a modem (DCE equipment). Instructions for setting the jumpers are given later in this section.

553-3001-211 Standard 2.00 September 2004