Digital vs. Analog

Does it matter if I use Digital or Analog phone services?

YES, it does matter. Your TTY and telephone system may be seriously damaged if used incorrectly with a digital phone system.

Please refer to the following guidelines for using TTYs with analog or digital telephone equipment.

In General:

• TTYs can be used with digital office phones acoustically by placing the telephone handset into the TTY acoustic cups.
• TTYs should NOT be plugged directly into a digital telephone network unless:
• there is a separate analog line, or
• there is an analog port, or 
• there is an analog converter available
• The TTY and/or the digital network can be damaged if the TTY is plugged directly into a digital jack.

At Home:

Most telephone lines coming into homes are analog. TTYs can be plugged into any standard phone jack in your home. If you have a special telephone line for ISDN connections for a computer user, however, do not plug the TTY phone line into this jack. On the other hand, DSL lines (also used for computers) generally include analog frequencies, so it is OK to directly attach a TTY on a DSL line.

It is always safe to use the TTY in acoustic mode by placing the telephone handset into the TTY cups.

At the Office:

Most office telephone systems (as well as hotels and hospitals) use digital telephone lines such as ISDN, PBX or T1 lines. Often, these office telephone systems can also provide an "analog" port or jack connection within the system. Sometimes workstations have two phone jacks, one to connect the office telephone to the digital system and the other for an analog connection. It is possible that one of these jacks may be used to connect a fax machine or modem, which may also use analog connections.

In hotels, an analog phone jack is sometimes provided on the side of a hotel telephone. Individuals use this analog connection to plug in their laptop computers. This same jack can be used to directly connect your TTY. If this analog jack is not available you can still use the TTY acoustically by placing the telephone handset on the cups. Remember that a TTY can only be plugged directly in the telephone jack when it is an analog jack. It is always safe to use the TTY in acoustic mode in places that have a digital phone system.

With Cellular Phones:

Currently, TTYs can be used with analog cellular telephones. Digital cellular telephones are not yet capable of sending and receiving the TTY tones without numerous character errors.

With Cordless Telephones at Home:

Cordless home telephone are now available in digital technology, which gives users clear communication over a greater distance. Digital cordless telephones with headset or hands-free jacks can be used with TTYs that include a 2.5mm audio jack (such as the Ultratec EZcom Pro/C and the Ultratec Compact/C)