Ccitt V.35 / Mrc 34 Interface - Canoga Perkins 2240 User Manual

2240 Fiber Optic Modem

4.6.2.1 CCITT V.35 / MRC 34 Interface

This interface complies with CCITT Standard V.35 and ISO 2593-1993. Electri-
cal characteristics comply with V.35 for clock and data signals and RS-232 levels
for control signals.
This interface uses the physical connector type and pinouts specified in ISO 2593-
1993 (refer to Table 4-K). The V.35 interface uses a 34-pin female Winchester
connector for the physical connection.
Note that the table lists the function name shown in ISO 2593 and an aka where
applicable. The rest of this section refers to the ISO 2593 function name and aka
interchangeably. For example, the aka Serial Clock Transmit (SCT) is the same
as ISO 2593 Transmitter Signal Element Timing.
The TXD, RXD, SCT, SCR and SCTE pins carry the primary data and clock
signals (conforming to the V.35 standard). In addition, an extra clock signal input
is provided to make the 2240 / -MC2 combination more "DTE-like" in tail circuit
applications at the clock source end (refer to Section 2.2.6). The remainder of the
pins are either ground references or control signals. Transmit Data (TXD) and
Receive Data (RXD) are the data input and output signals for the modem, respec-
tively.
Serial clock Transmit (SCT) is the modem's transmit clock reference output that is
used for the internal and slave clock modes. Serial Clock Receive (SCR) is the
clock signal for the receive data unless the 2240's main PCBA W26 (XTCLK)
jumper is ON, in which case the Extra Clock input signal is used to shift receive
data out from the 2240 (refer to Section 2.2.6). Serial Clock Transmit External
(SCTE) is the transmit clock signal used in either of the External clock modes or
when the main board's internal CLK / EXT switch is set to EXT (refer to Section
3.7).
Two end-to-end control leads are provided as part of this interface. An input to
RTS is transmitted to the DCD output at the other end of the link (see description
of RTS-Bias jumper and DCD jumper). CTS (Clear to Send) follows RTS locally
but is delayed approximately 1 millisecond when RTS turns ON (see description
of CTS-Gate jumper). The other end-to-end control lead pair is listed below with
the input signal listed first:
DTR to RI
This path, in conjunction with crossover cables at the DTR end, can be used to
implement incoming call handshaking.
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