| Siecor brochure, "Siecor Introduces New Multiline NID Solutions", Siecor Corp., Hickory, N.C. |
| Keptel brochure, "SNI-5000, Tomorrow's Network Interface System Today", Keptel Inc., 1985. |
| GTE brochure, "Weatherproof, Corrosion Proof . . . and We Guarantee It", Sylvania GTE Control Devices, Dec. 1984. |
| Lipincott brochure, "GL-700 Multi-Unit Network Interface Device", Lippincott Industries, Spokane, Washington, May 1988. |
| Lippincott advertisement, vol. 211, Telehony, Sep. 9, 1986. |
| GTE brochure, Protected Terminating Device NI-2006, GTE Control Devices, Standish, ME, May 1992. |
| GTE brochure, Protected Terminating Device PTD, GTE Control Devices, Standish, ME, May 1992. |
| GTE brochure, Protected Terminating Devices NI-2025, NI-2050, NI-2100, NI-2200, GTE Control Devices, Standish, ME, May 1992. |
| GTE brochure, Introducing the Next Step In the Evolution of Network Interface Technology, GTE Control Devices, Standish, ME, May 1992. |