TLS-D-01电话线路模拟器：
The 5C is the basic TLS-5 model. Features include:
Four loop start lines
Two talk paths
Programmable parameters:
; Primary/secondary telephone numbers up to 16 digits
; Ring cadence (distinctive ringing)
; Off-hook modes
; Network response time delays
; Test tone frequency and cadence
; Eight selectable ring waveforms
; Line attenuation
; Forced disconnect
Dial up test tones
