Inbound PCI/Virtual Terminal Calls Capturing Only Partial DTMF Digits (Intermittent)

Diagnosis

1) Understand the symptom

During inbound calls where the caller enters card details using DTMF (phone keypad tones), the PCI/Virtual Terminal flow may capture only part of the digits. A common symptom is:

• “our system will only record 8-10 digits, even after re-trying”

This does not occur on every inbound call (intermittent). In many cases, payment collection succeeds when the agent calls the customer directly (outbound call).

2) Conditions commonly associated with the issue

• Reported predominantly on mobile-originated inbound calls.
• Calls traverse multiple upstream networks before reaching the PCI platform.

3) Provider findings (why digits may be missed)

DTMF inconsistencies can occur when signaling behavior changes across networks or mid-call. Examples include:

• DTMF delivery switching between RFC2833 and inband tones between networks or mid-call.
• Inband tones arriving with poor audio quality or insufficient duration.
• The PCI platform is primarily configured to receive digits using RFC2833 (and can accept inband), but method changes mid-call can cause digits not to be detected.

In the reviewed examples, the observed failure rate was approximately ~0.6%, and provider logs showed many successful digit-capture calls during the same periods. This pattern aligns with upstream/network delivery behavior rather than a platform-wide defect.

4) Call path (generalized)

Multiple upstream networks may be involved before digits reach PCI capture:

Caller handset → originating mobile carrier → <callstream_inbound_number> → <upstream_carrier_or_transit_network> → BCH PCI platform

Solution

5) Recommended workaround / mitigation

If inbound digit capture fails:

1. Ask the caller to re-enter the digits once (if your process allows a retry).
2. If the issue persists, place an outbound call to the customer and collect payment that way (different call paths can allow payment to be collected successfully).

Data to Collect for Escalation

If you need to escalate further (for example, to your carrier or telephony provider for route and DTMF signaling review), collect examples including:

1. Caller number (or masked identifier per your policies)
2. Date/time of the call (include timezone)
3. Call reference ID and/or transaction reference ID
4. Digits entered vs. digits captured (e.g., “16 entered, 10 captured”)
5. At least one successful call example for comparison

Validation

To validate the mitigation and confirm the likely cause:

1. Identify an instance where a payment attempt fails on an inbound call (partial digits captured).
2. Retry the payment collection via an outbound call to the same customer.

Success criteria: Full card digit capture occurs consistently on the outbound path, while inbound failures (if they occur) remain intermittent—supporting upstream DTMF variability as the cause.

What This Is / Is Not

• Not identified as a CallStream/BCH PCI platform defect based on provider review; no corrective platform-side change is available from these findings.
• Most likely upstream network behavior affecting DTMF transmission on certain inbound routes/calls (for example, switching between RFC2833 and inband, or poor inband tone quality/duration).