These points were made in testimony yesterday by Glenn A. Robinette, a security systems contractor, and Noel C. Koch, former principal deputy assistant secretary of defense for international security affairs:

ON NORTH'S SECURITY SYSTEM:

Robinette testified that Lt. Col. Oliver L. North, the former White House aide, helped create a trail of fake documents to conceal the fact that retired Air Force major general Richard V. Secord paid for a $13,873 security system at North's suburban Virginia home.

Robinette said that in December, shortly after North was fired when information about the Iran-contra affair became public, North called him and the two exchanged backdated letters that made it seem as if North was offering to pay for the system.

Robinette, a former CIA employe who testified under a grant of limited immunity, said the system was installed at Secord's request and paid for by him in mid-1986 after North had been subjected to harassment. Federal employes are forbidden by law to accept gratuities.

Secord, who worked closely with North, was a partner in the firm that sold arms to Iran and diverted some of the profits to aid the Nicaraguan contras.

ON SECORD'S LEGAL DEFENSE:

Koch said he resigned last Friday as trustee of a fund established for Secord's legal defense after $500,000 was transferred from Swiss bank accounts to the fund during the last six weeks.

Koch said transfers of that size from a Swiss bank had a "peculiar odor."

ON THE BEIRUT HOSTAGES AND THE PRESIDENT

Koch said North told him in the fall of 1985 that the hostage matter was "eating" at the president and that Reagan wanted the hostages home by Christmas.

He said North said the president is "driving me nuts about it."