Black Box 5000 manual SF, single frequency See tone signaling

RS-422— An EIA-recommended standard for cable lengths that extended the RS-232 50-foot limit. Although introduced as a companion standard with RS-449, RS-422 is most frequently implemented on unused pins of DB25 (RS-232) connectors. Electrically compatible with CCITT recommendation V.11.

RS-423— An EIA-recommended standard for cable lengths that extended the RS-232 50 foot limit. Although introduced as a companion standard with RS-422, RS-423 is not widely used. Electrically compatible with CCITT recommendation V.10.

RS-449— An EIA-recommended standard for the mechanical characteristics of connectors; introduced as a companion standard to RS-422 and RS-423. It specifies two connectors (a 37- pin connector and a 9-pin connector); not widely used.

RS-530— An EIA-recommended standard for the implementation of standard RS-422 or RS-423 Driver/Receivers on a 25-pin connector (DB25). It is intended as a replacement for RS- 449 for most data services using the same connector as RS-232.

RTS, request-to-send— An RS-232 interface signal, sent from a DTE to the DCE, that indicates the DTE has data to transmit.

RX, receive — An abbreviation meaning receive or reception.

self-test— A diagnostic feature used to test the voice/fax channel locally that does not include the link.

SF, single frequency — See tone signaling.

shroud — The part of a Multiserver stacking connector that is mounted on the underside of a module.

signaling — A handshaking protocol used between telephone equipment. Includes supervising (on/off hook line status), alerting (ringing), and call addressing (dialing) for switched services.

Glossary

signaling options — Options related to signaling that are configurable in the voice/fax module. When the Multiserver is strapped for KTS, the options include repeated ringing, interrupted 2/4 ringing, and interrupted 2 ring 1/2. When the Multiserver is strapped for E&M, the options include DC and 2280 tone. See also DC signaling and tone signaling.

sign-on character — The first character sent on an ABR circuit. It is used to determine the data rate.

single frequency — See tone-signalling.

slow busy signal —

•In a switching mode, the response to a call attempt when the called extension is busy.

•In a force-connect mode, the signal heard when a sync loss occurs (link goes down).

software reset — A reset performed in the Command Facility Main Menu or in the LCD/Keypad menu. This may be a warm or cold start.

SOH, start of header — A control character used to indicate the beginning of a message header.

space — A binary 0 in data communications.

spacer — A piece of the Multiserver hardware that separates one module from another.

stacking connector — A coupling containing electrical pins or sockets that are located on the top and bottom of a module board to connect electrical wires from one module board to another. The connector on the underside is referred to as a shroud, and the connector on top is referred to as a block.

start bit — The first bit in asynchronous transmission. It is used to indicate the beginning of a character.

stop bit — The last bit in asynchronous transmission, used to indicate the end of a character.

261