Changing SGP Electrical Interfaces

The base SGP has an RS-232 electrical interface. This can be changed to a different electrical interface by adding a daughter card. For the SG2P, the electrical interface of each link can be set individually. For the SG4P, links 0 and 1 will have the same electrical interface, as will links 2 and 3.

If your SGP was not ordered with an alternate electrical interface, you can change it from RS-232 to V.35, V.36 or X.21 with the following steps:

  1. Remove the RS-232 driver chips.

    Each link has two socketed RS-232 driver chips that must be removed before the daughter card is put in place.
    On the SG2P: For link 0, remove U8 and U9. For link 1, remove U11 and U12.
    On the SG4P: For links 0 and 1, remove U8, U9, U11 and U12. For links 2 and 3, remove U17, U18, U20 and U21.

  2. Place the daughter card in the interface option mount.

    The header next to the RS-232 driver chips that were removed holds the daughter card. The card should be mounted so that the header is on the left and the majority of the card faces away from the back panel connectors. Be careful to insert it so that all of the pins daughter card go into holes of the header.

  3. Label the back of the card.

    As the cards use the same back panel connectors independent of the electrical interface, it is strongly recommended that you label the outside of the card's back panel to indicate the electrical interface.