Digi 34 Specifiche Scaricare il pdf (Pagina 9)

10 Chapter 3 EIA-232 asynchronous interface

Data rate vs. cable length recommendations

• The maximum length is the amount of cable that is connected to a

Digi supplied interconnect device, such as Quad or Octa cables and

boxes.

• The maximum length is based on a cable rated at the following:

- 12.3 pF/foot, conductor to conductor

- 22.4 pF/foot conductor to shield

• In situations where low-capacitance cable is unavailable, or very

long cable runs are required, “short-haul” modems can be used to

increase the effective range of the EIA-232 interface. Short-haul

modems are similar to standard modems, except that they are

connected directly to each other via a cable instead of going through

a telephone circuit.

• Use only externally-powered short-haul modems with Digi products.

Resolving transmission errors

If transmission errors occur, follow this procedure to determine the cause of

the problem:

1. Reduce the baud rate.

2. Reduce the cable length.

3. Use a cable with a lower capacitance per foot rating.

Data rate (bps) Maximum cable length

57,600 or less 100 feet

115,200 80 feet

230,400 40 feet

460,800 20 feet

921,600 10 feet

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Digi 34 Specifiche Pagina 9