CT0, CT1, CT2 Cordless Phones: Standards & Differences

This article breaks down the key differences between the CT0, CT1, and CT2 analog cordless telephone standards. “CT” is simply short for “Cordless Telephone.” Let’s dive in.

CT0

Here’s a look at the characteristics of the CT0 analog cordless telephone standard:

• Mobile Frequency (MHz): Varies significantly by region:
  • UK: 2/48
  • France: 26/41
  • Australia: 30/39
  • Netherlands & Spain: 31/40
  • China, South Korea, Taiwan, USA: 46/49
  • China (again): 48/74
• Duplex Scheme: FDD (Frequency Division Duplexing)
• Multiple Access Type: FDMA (Frequency Division Multiple Access)
• Number of Channels: Typically 10, 12, 15, 20, or 25
• Channel Spacing (KHz): 1.7, 20, 25, or 40
• Modulation Technique: FM (Frequency Modulation)

CT1 and CT1+

Now, let’s examine the features of the CT1 and CT1+ cordless telephone standards:

• Mobile Frequency (MHz):
  • CT1: 914 and 960
  • CT1+: 885 and 932
• Duplex Scheme: FDD (Frequency Division Duplexing)
• Multiple Access Type: FDMA (Frequency Division Multiple Access)
• Number of Channels:
  • CT1: 40
  • CT1+: 80
• Channel Spacing (KHz): 25
• Modulation Technique: FM (Frequency Modulation)

CT2 and CT2+

Finally, we’ll explore the characteristics of the CT2 and CT2+ analog cordless telephone standards:

• Mobile Frequency (MHz):
  • CT2: 864 and 868
  • CT2+: 944 and 948
• Duplex Scheme: TDD (Time Division Duplexing)
• Multiple Access Type: TDMA/FDM (Time Division Multiple Access / Frequency Division Multiplexing)
• Number of Channels: 40
• Channel Spacing (KHz): 100
• Users per Channel: One
• Modulation Technique: GFSK (Gaussian Frequency-Shift Keying), using a 0.5 Gaussian filter
• Channel Data Bit Rate (Kbps): 72