Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
RFL VF-5A RFL Electronics Inc.
June 28, 2005 18 (973)
334-3100
Type III. Type III signaling is a partially looped four-wire scheme. It provides better protection
against interference, and is used with electronic switching systems. An on-hook (idle) condition is
indicated by an open circuit on the E lead and ground on the M lead. Signaling over the M lead is the
same as Type I, except that battery and ground for M lead signaling are provided to the trunk circuit
over the MB and EB leads. A distinction of the Type III interface is that three conductors are used for
M lead signaling.
ALERTS AND ALARMS
The RFL VF-5A reports no module-level ALERT or ALARM signals to the shelf Common Module.
COMPATIBILITY WITH RFL VF-5 MODULES
RFL VF-5A modules are compatible with older RFL VF-5 modules; a circuit may consist of an RFL
VF-5 at one end, and an RFL VF-5A at the other. However, there are a few differences between the
two:
1. The RFL VF-5A is remote controllable; the RFL VF-5 is not.
2. On the RFL VF-5, DIP switch SW1 is unused except for SW1-8; this is the Channel 2 ON/OFF
switch. On the RFL VF-5A, SW1 is used to set the module's remote access address (SW1-1
through SW1-6), set the module to local or remote control (SW1-7), and turn service on and off
(SW1-8).
3. The RFL VF-5A has a jumper (E5) which acts as the Channel 2 ON/OFF switch. The RFL VF-5
has no E5 jumper
ATTENUATOR SETTINGS
The RFL VF-5A module has four attenuators: Channel 1 Transmit, Channel 1 Receive, Channel 2
Transmit, and Channel 2 Receive. Factory settings for these attenuators are 3.0 dB on the transmit side,
and 3.0 dB on the receive side. This allows -16 dBm in, +7 dBm out with 3 dB of headroom.
Table 4 is an extended list of attenuator calibration settings. Set the attenuators based on the desired
input and output levels listed in the table. These settings will permit a maximum signal level 3 dBm
higher than the indicated level. For example, with -10 dBm input, the transmitter attenuator setting
would be 9 dB and the maximum line input would be -7 dBm. Using these settings on the transmit side
will place a signal of 1 digital mW into the transmission bitstream.
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