GAI-Tronics L3149B C200 Advanced Deskset - Manual (Page 39)

L3149B (C200) Advanced Tone Remote Desk Set Installation
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Relay Control
N OTE : The following optional features require relay control option equipment (Kit No. XRC0001A) on
the L3149B. Maximum load ratings for each relay output are 1 A @ 125 V ac and 2 A @ 30 V dc.
E&M
The XAC0008A Programming Software can be used to configure the L3149B for Local and E&M
control. The unit can be configured for either E&M control or E&M with tone control. Two pairs of
leads control communication between the desk set and the base station.
The desk sets use the M-lead to signal when to transmit and the E-lead to detect when to receive. Note
that the E-lead is not required. The M-lead must be programmed on the relay module using the
XAC0008A C200 Programming Software.
E-Lead
In systems requiring full-featured E&M control, the input can be configured as an E-lead to indicate an
unsquelched condition. The desk set uses this input as a VOX indicator, so when asserted, generates a
VOX condition. However, the speaker squelch is operated by voice activity.
M-Lead
A closure is needed to act as the M-lead, which is the relay closure. The M-lead is closed depending on
the type of configuration and the type of transmission, only during a non-intercom transmission.
 When configured as E&M control, the relay is closed only when a transmission requiring transmitter
keying is needed.
 When configured as E&M with tone control, the relay is closed whenever a non-intercom
transmission is done.
E&M with Tone Control
E&M with tone control is used for transmitting control tones using an RF device. The M-lead is used to
assert PTT of the device, allowing transmission of the control tones to a remote adapter with a receiving
RF device. The unit must be configured for Tone with E&M, and the M-lead must be set on relay
module. Note that the HLGT duration may need to be increased to allow the RF device time to key up
and transmit to the receiving device.