Parallel port question

Question

I am looking to buy a computer to drive a metal cutting table for my machine shop. The machine interfaces to the computer through the computer's parallel port through an IEEE 1284 cable. The manufacturer warns that the computer's port must be configurable to EPP and be a 5 volt port rather than a 3.3 volt port but will give no computer recommendation. Does anyone know if the current 170L Optiplex with the P4 processor meets this requirement?

Dev Mgr · Answer

The documentation on the system setup shows that the parallel port supports EPP. I'm not sure about those voltages, as I couldn't find that documented.

snapohead · Answer

As far as i'm aware, all parallel ports run at 5 volts.

speedstep · Answer

@snapohead wrote:
As far as i'm aware, all parallel ports run at 5 volts.

The problem is that some devices expect that there will be a lot of 5v signals that you can drain power from.

One fix for this is to make a passthru connection and add power that way.
Some vendors do that.

The Driver has a slew rate of 0.05v/nS - 0.40v/nS, with an impedance of 50 ohms +/- 5 ohms at half of Voh
The maximum output voltage is +5.5v, the minimum voltage is -0.5v.
The steady state high output is +2.4v [minimum] with 14mA of source current
The steady state low-level output is +0.4v [maximum] with a source current of 14mA

The Receiver will operate with a maximum input voltage is +7.0v, the minimum voltage is -2.0v.
The steady state high input is +2.0v [minimum] with 20uA of source current
The steady state low-level input is +0.8v [maximum] with a source current of 20uA
The Receiver has needs to provide between 0.2v and 1.2 volts of input hysteresis

The 1284 standard defines two levels of interface compatibility, Level I and Level II. The Level I interface is defined for products that are not going to operate at the high speed advanced modes, but need to take advantage of the reverse channel capabilities of the standard. The Level II interface is for devices that will operate in the advanced modes, with long cables, and at the higher data rates.

Compatibility mode; Centronics type operation (PC to Peripheral), providing the original (required) control signaling bits. These bits include 8 data lines, a Strobe, a Busy, an Acknowledge, a Select, Paper Empty, Fault, Initialize Printer, Select Printer, and a Auto Feed line. Compatibility mode is the basic mode of operation, asychronous, byte wide operation with a transfer rate of between 50kBps to 150kBps.

Nibble mode; 4 bit data bus (Peripheral to PC), 8 bit data bus (PC to Peripheral); supporting uni-directional printer interfaces. This provides an interface which operates full speed forward and half speed in reverse. The transfer rate is between 50kBps to 150kBps

Byte mode; 8 bit bi-directional bus. Normal port operation. The transfer rate is between 50kBps to 150kBps

ECP; Extended Capabilities Port. Allowed the PC to send 32 bit data to the port, than letting the port divide up the data into four 8 byte messages, improving system (PC) operation. Transfer speeds are ten times faster then the previous modes.

EPP; Enhanced Parallel Port; Allows high-speed transfers of bytes in either direction. EPP is used with real time controlled peripherals. EPP transfer times are the same as ECP transfer rates.

Startek makes 32 bit 5v PCI 2.1 cards for this.
http://www.buy.com/retail/product.asp?sku=10248787