PTT-2 Push to Talk Lockout Device, 2 channel in and 1 channel out with priority keying lockout

PTT-2 Front Picture PTT-2 Rear Picture
  • Use to de-key radios on Busy/Idle T1 trunks
  • Industrial temperature rated -40 to +70 C
  • One control port unlocks multiple user ports when E&M is used to key radios
  • Supports Tie Line Types I, II IV and V
  • Units can be daisy changed, using a single control port
  • Industrial temperature rated -40 to +70 C
  • 1U high, may be rack shelf mounted
  • Compact size
  • DIN rail clip option
  • AC and DC power supply options
  • Proudly manufactured in the United States of America

The PTT-2 is a Push-to-Talk lockout device. It is used with multiple E&M circuits linked to radios. The PTT-2 solves the problem of radio transmitters being locked into a Transmit ON state when a T1 circuit fails. Many T1 trunk lines will go into a busy condition when the T1 trunk fails. This causes the E&M leads to lock in an ON state, which causes radio transmitters to lock in the ON state.

The PTT-2 uses one control E&M circuit for 2 or more active E&M channels that are connected to radios, where the radios use the E&M to key the radio transmitters. The PTT-2 control E&M channel monitors its E&M leads. The control channel is not used for analog traffic, only for the purpose of E&M signal monitoring. If the control channel circuit goes into a mode where the E&M leads turn on, the PTT-2 assumes the T1 has failed. The PTT-2 then de-asserts the E&M leads of the operational channels 1 and 2.

The PTT-2 units can be daisy chained. This allows a single control port to serve 2, 4, 6, 8, etc. radio E&M audio channels.