Interface Adapters

Introduction

The composite link, high speed (HS) data channel, and FRAM-01 expansion card can use different electrical interfaces. FRAM-01 interfaces are described in Chapter 7.

The default interface for the Composite Link and High Speed Data channel is RS-232. However, the composite port is capable of rates up to 128 kbps and the high speed data channel support rates up to 64 kbps. At such high speeds, operations using the RS-232 interface may cause transmission errors.

To support higher speeds, the base unit provides two plug-in slots for interface cards which redefine the composite and high speed data channel interface. If an interface card is installed into the composite slot, the composite link is redefined to the electrical interface associated with the interface card. If an interface card is plugged into the high speed data channel slot, the HS data channel interface is redefined to the electrical interface associated with the interface card.

In both cases, a connector conversion cable is used to change the DB25 connector (for composite or High Speed) on the rear of the unit to the appropriate connector type and gender.

Interface Card Types

Interface Cards are available in kit form. The interface adapter kit for both the composite link and the high speed data channel consists of two components: a plug-in card for electrical interface conversion and a cable for connector conversion.

Three following electrical interfaces are available: V.11/X.21, V.35, V.36, and RS-449. The converter cable provides either a DTE or DCE interface to the link equipment or connected channel device (converting the standard DB25 connector on the FastPAD). By combining these options, several interface card kits are available.

FastPAD Interface Cards

Table 5-1 identifies the Interface Cards that can be used in FastPAD units:

Table 5-1: Interface Card Kits

Model	Description
ICARD-1A	V.11 Interface Kit FastPAD to DTE (term.)
ICARD-1B	V.11 Interface Kit FastPAD to DCE (modem)
ICARD-3A	V.35 Interface Kit FastPAD to DTE (term.)
ICARD-3B	V.35 Interface Kit FastPAD to DCE (modem)
ICARD-3D	128 Kbps Internal Clock V.35 Interface Kit FastPAD to DCE (modem)
ICARD-4A	RS-449 Interface Kit FastPAD to DTE (term.)
ICARD-4B	RS-449 Interface Kit FastPAD to DCE (modem)
ICARD-4D	128 Kbps Internal Clock RS-449 Interface Kit FastPAD to DCE (modem)
ICARD-6B	V.35 Interface kit FastPAD to DCE (modem)

Note Interface Card-3D and Interface Card-4D kits are designed specifically for interfacing with satellite modems operating at 128 Kbps and which require the FastPAD to loop the modem's receive clock back to the modem's ext transmit clock.

Note Typically, an "M" following the connector type indicates the connector is Male; an "F" indicates a Female connector. One end of the cable is always DB25 male for connecting to the DB25 female connector at the rear of the FastPAD.

Note The composite port always connects to a DCE device like a modem or DSU. If an Interface Card kit is to be used on the composite port, it should be "B" or "D" type (e.g., for a V.35 composite, an Interface Card-3B kit should be used).

Installation

The following describes how to install FastPAD and the FastPAD Micro devices.

FastPAD

Remove the interface card from its shipping carton and insert it into the composite link or high speed channel interface slot on the baseboard. Place the card into its slot with component side facing the power supply cage.

Connect the DB25 male connector of the corresponding adapter cable to the DB25 female connector on the back of the FastPAD. Tighten the screws provided on all connectors.


	Warning Power MUST be OFF before removing or inserting Interface Cards.

FastPAD Micro

The Interface Card connector slots in a FastPAD Micro are located on the baseboard next to the power supply. Complete the following steps to install a High Speed or Composite Link Interface Card.


	Warning Interface cards MUST be installed with the component side of the Interface Card facing AWAY from the power supply. Improper installation will result in damage to the Interface Card. Make sure the power is OFF before removing or installing an Interface Card.

Step 1 Remove the interface card from its shipping carton.

Step 2 Insert the connector edge of the Interface Card into the High Speed or Composite Link connector on the base card. The component side of the Interface Card must face the right side of the unit-AWAY FROM THE POWER SUPPLY.

Step 3 Connect the DB25 male connector of the corresponding adapter cable to the DB25 female connector on the back of the unit.

Step 4 Tighten the screws provided on each connector.

Cable Lengths

Standard cables included with the interface card kits are 15 feet (4.57 meters) in length. Observe the following guidelines for any cables used:

Step 1 Use shielded cable whenever possible.

Step 2 Cables should be twisted pair wiring and made in accordance with standard wiring practices used for high speed cables.

Step 3 Do not use cables with conductors less than 24-gauge.

Step 4 The maximum length of each interface cable is greatly dependent on the quality of the cable, conductors, and connectors used in the cable's assembly.

Step 5 The recommended maximum length for each cable is defined in Table 5-2.

Table 5-2: Recommended Cable Lengths

Interface	Maximum Length
RS-449	150 Meters
V.11	150 Meters
V.35	50 Meters
V.36	50 Meters

Table of Contents

Interface Adapters